Benzopyran compounds as melanogenesis modifiers and uses thereof

ABSTRACT

Provided are benzopyran compounds of formula I, for example, pomiferin-3′,4′-dimethyl ether, and the use of such compounds and compositions thereof to modulate (e.g., inhibit) melanogenesis and pigmentation. 
     
       
         
         
             
             
         
       
     
     wherein R 3 , R 4 , R 5 , R 6 , R 7  and R 8  are described herein. Also provided are plant extracts containing a compound of formula I, and the use of such a plant extract to modulate (e.g., inhibit) melanogenesis and pigmentation. The compound or plant extract may be prepared as pharmaceutical and cosmetic compositions, and may be used for the prevention and treatment of conditions that are related to aberrant melanogenesis activity.

RELATED APPLICATION

The present application claims the benefit under 35 U.S.C. §119 of U.S.Provisional Application Ser. No. 61/436,869 filed Jan. 27, 2011. Thecontent of said provisional application is hereby incorporated byreference in its entirety.

GOVERNMENT RIGHTS

This invention was made in part with government support under Grant No.AR41880 awarded by the National Institute of Health. Accordingly, theUnited States Government has certain rights in the invention.

FIELD OF THE INVENTION

The present invention relates to the identification of benzopyrancompounds that modulate melanin synthesis (melanogenesis), and the useof such compounds and compositions thereof to modify (e.g., inhibit)melanin production. This invention also relates to methods forpreventing and/or treating conditions that are causally related toaberrant melanogenesis activity, such as comprising (but not limited to)pigmentation abnormalities and hyperpigmentation, using the compounds ofthe invention. It is to be understood that such compounds may be usedeither alone or in combination with other compounds having the activityset forth herein.

BACKGROUND OF THE INVENTION

Several publications and patent documents are referenced in thisapplication in order to more fully describe the state of the art towhich this disclosure pertains. The disclosure of each of thesepublications and documents is expressly incorporated by referenceherein.

Melanocytes synthesize melanin inside specialized organelles calledmelanosomes (reviewed in Orlow, 1998, in The Pigmentary System:Physiology and Pathophysiology 97, Oxford University Press, New York,Nordlund et al., eds). Melanosomes are formed by the fusion of two typesof vesicles. Melanin is a dark biological pigment (biochrome) found inthe skin, hair, feathers, scales, eyes, and some internal membranes ofmany animals that confers protection against ultraviolet radiation. Seehttp://www.britannica.com/eb/topic?idxStructId=460219&typeId=13;http://www.britannica.com/eb/topic?idxStructId=126546&typeId=13;http://www.britannica.com/eb/article-9109619.

Melanism refers to the deposition of melanin in the tissues of livinganimals, the chemistry of which depends on the metabolism of the aminoacid tyrosine. More specifically, melanins are formed as an end productduring metabolism of the amino acid tyrosine. Seehttp://www.britannica.com/eb/topic?idxStructId=611971&typeId=13. Defectsin the production of melanin and deposition of melanin (i.e., melanism)can result in pigmentation deficiencies such as albinism.

The ability to control melanin synthesis, which in turn, alters skinpigmentation, may be used advantageously to address a variety ofhealth-related conditions, as well as cosmetic objectives. Decreasingpigmentation is a desirable outcome in the treatment of disorders suchas melasma, chloasma, post-inflammatory hyperpigmentation, solarlentigines, and the like.

The ability to modify skin coloring has generated considerable interestin many cultures. Inappropriate production or overproduction of melaninis considered a cosmetic problem by many individuals. In particular, theability to remove hyperpigmentation, such as that found in age spots,freckles or aging skin generally, is of interest to individuals desiringa uniform complexion. Moreover, since chloasma, freckles, and pigmentarydeposits that appear after over-exposure to the sun tend to occur orincrease in frequency in middle aged and elderly individuals, suchconcerns are amplified in aging individuals. Indeed, with advancingyears, these pigment deposits typically take longer to disappear and aremore likely to become permanent. In certain areas of the world, generalbody whitening is also desirable.

A number of products have been developed to affect a decrease in skinpigmentation. One such product contains hydroquinone, a well knownactive substance for skin de-pigmentation, as described in U.S. Pat. No.6,139,854. Hydroquinone can, however, have serious side effects ifapplied over a long period of time. The application of hydroquinone toskin may, for example, lead to permanent de-pigmentation, which resultsin increased photosensitivity of the skin upon exposure to ultravioletlight. Hydroquinone can be administered in combination with cortisone(which can thin the skin and cause other problems following facialadministration), retinoic acid (an irritant), or glycolic acid (anirritant) to increase the efficacy of hydroquinone.

A variety of other substances have been proposed for use as regulatorsof skin pigmentation. Almost all of these substances work by eitherbleaching existing pigment or preventing new pigment synthesis byinhibiting the activity of tyrosinase, the principal rate limitingenzyme in the production of melanin. U.S. Pat. No. 6,123,959, forexample, describes the use of aqueous compositions comprising liposomesand at least one competitive inhibitor of an enzyme involved in melaninsynthesis. U.S. Pat. No. 5,132,740 describes the use of certainresorcinol derivatives as skin lightening agents. WO 99/64025 describescompositions for skin lightening which contain tyrosinase inhibitingextracts from dicotyledonous plant species indigenous to Canada. U.S.Pat. No. 5,580,549 describes an external preparation for skin lighteningcomprising 2-hydroxybenzoic acid derivatives and salts thereof asinhibitors of tyrosinase. WO 99/09011 describes an agent for inhibitingskin erythema and/or skin pigmentation, containing at least onecarbostyril derivative and salts thereof. U.S. Pat. Nos. 5,214,028 and5,389,611, describe lactoferrin hydrolyzates for use as tyrosinaseinhibitory agents.

In WO 02 98347, Manga describes methods for identifying compounds thatalter melanogenesis in melanogenic cells, more particularly, compoundsthat inhibit or enhance P protein function. This method is based, inpart, on the observation that P protein function is required for propercellular localization of tyrosinase and other melanosomal proteins, andis required for both full tyrosinase activity and melanogenesis inmelanogenic cell types.

Orlow et al. describe screens for identifying compounds that inhibit orincrease melanogenesis in melanogenic cells. See WO 01 1131. Thesestudies were based upon the discovery that some compounds that inhibitmelanogenesis do so by causing a mislocalization of tyrosinase, the keyenzyme in melanin synthesis.

Other studies are directed to methods and compositions for increasingmelanogenesis. U.S. Pat. No. 5,352,440, for example, is directed toincreasing melanin synthesis in melanocytes and increasing pigmentationby administration of certain diacylglycerol compounds. U.S. Pat. No.5,532,001 is directed to increasing pigmentation in mammalian skin viaadministration of certain DNA fragments. U.S. Pat. No. 5,554,359 isdirected to increasing levels of melanin in melanocytes byadministration of lysosomotropic agents. U.S. Pat. Nos. 6,750,229 and6,995,804 are directed to the identification of protease-activatedreceptor-2 (PAR-2) pathway and nitric oxide synthesis modulators,respectively, and their use in modulating pigmentation levels.

As described above, many methods have been proposed to achieve desiredpigmentation levels of the skin. Such methods have included kojic acid,hydroquinone, retinoids and other chemical compounds for depigmentationpurposes. The value of many of these compounds and compositions thereof,however, has been questionable. Precise application of all thesecompounds is necessary in order to achieve the desired result since adistinct line of demarcation between treated versus non-treated areas ofthe skin is frequently apparent. Moreover, many of these compounds causeskin irritation and, therefore, use of such compounds has undesirableside effects, particularly for long-term use.

SUMMARY OF THE INVENTION

The present invention is directed to compounds that may be identified bycell-based assays, which compounds control melanogenesis. In brief,compounds were screened in cell-based assays to identify compoundscapable of controlling, and particularly, inhibiting melanogenesis.Details pertaining to the screening assays are described in the Examplesbelow. The results of the screening assays identified a plurality ofcompounds that modify (i.e. inhibit) melanogenesis, some of which werenot previously known to exhibit such activity and others of which areknown to affect melanogenesis. Notably, the confirmation of the activityof known modifiers of melanogenesis in the present screen corroboratesthe validity of the techniques and experimental approach.

As such, disclosed herein are embodiments directed to the identificationof previously unidentified benzopyran melanogenesis inhibitors, andtheir use in controlling (e.g. reducing) pigmentation in in vitro and invivo applications. The disclosure further provides methods ofadministering the benzopyran melanogenesis inhibitors as an extract, oras a purified compound. The method optionally includes obtaining aquantity of plant matter from a plant of the osage family, optionallycomminuting the plant matter, contacting said plant matter with anextraction medium, and separating the plant matter from the extractionmedium.

The novel melanogenesis modifiers include compounds represented byformula I:

wherein

R³ is selected from H, halo, substituted or unsubstituted alkyl,substituted or unsubstituted alkenyl, or substituted or unsubstitutedaryl; and substituted or unsubstituted heteroaryl;

R⁴ is selected from H, halo, hydroxy, alkoxy, alkenyloxy, substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, andsubstituted or unsubstituted phenyl;

each R⁵, R⁶, and R⁸ is independently selected from H, halo, hydroxy,alkoxy, alkenyloxy, substituted or unsubstituted alkyl, substituted orunsubstituted alkenyl, and substituted or unsubstituted phenyl;

R⁷ is selected from H, halo, hydroxy, alkoxy, alkenyloxy, substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, orheterocycloalkyl; or R⁷ is —P(═O)(alkoxy)₂, or —P(═S)(alkoxy)₂; or

R⁶ and R⁷ or R⁷ and R⁸ are joined to form a 5- or 6-memberedheterocycloalkyl or heterocycloalkenyl; and the heterocycloalkyl orheterocycloalkenyl is unsubstituted or substituted with one more groupsselected from alkyl, alkenyl, hydroxyalkyl, acyloxyalkyl, hydroxy, andalkoxy;

or pharmaceutically acceptable salts, solvates, isomers, tautomers,metabolites, analogs, isotopic variants or prodrugs thereof.

In one particular embodiment, with respect to formula I, the compound isformula VIIb (osajin-4′-methyl ether):

or pharmaceutically acceptable salts, solvates, isomers, tautomers,metabolites, analogs, isotopic variants or prodrugs thereof.

In another particular embodiment, with respect to formula I, thecompound is formula VIIc (pomiferin-3′,4′-dimethyl ether):

or pharmaceutically acceptable salts, solvates, isomers, tautomers,metabolites, analogs, isotopic variants or prodrugs thereof.

Another aspect of the invention provides a method for preventing orinhibiting melanogenesis comprising administering an effective amount ofa compound of formula I.

Another aspect of the invention provides a method for promoting skinlightening comprising administering an effective amount of a compound offormula I.

In another aspect, the invention provides methods for inhibitingmelanogenesis using the compounds of formulae I-VIIc.

In another aspect, the invention provides methods for inhibitingmelanogenesis using a plant extract containing compounds of formula I.In one embodiment the plant extract is derived from the fruit of Maclurapomifera.

In another aspect, the invention provides methods for promoting skinlightening using the compounds of formulae I-VIIc.

In another aspect, the invention provides methods for promoting skinlightening using a plant extract containing compounds of formula I. Inone embodiment the plant extract is derived from the fruit of Maclurapomifera.

With respect to in vitro applications, test-tube based and additionalcell-based assays may be used to test the ability of modified versionsand/or compounds to alter melanogenesis. In vivo applications aredirected to the administration of at least one of the novelmelanogenesis modifier compounds to a subject desirous thereof or inneed thereof to control and/or to reduce pigmentation levels forprophylactic, therapeutic and/or cosmetic purposes.

In accordance with the disclosed embodiments, a method is presented foreffecting changes in mammalian skin pigmentation comprising topicalapplication of at least one benzopyran compound or a composition thereofto the skin of a mammal. Compositions disclosed herein may contain oneor more of the benzopyran compounds which have been identified asmodifiers of melanogenesis.

More specifically and with respect to those compounds capable ofreducing or inhibiting melanogenesis, the disclosed embodimentsencompass a method for decreasing pigmentation in mammalian skin, hairor wool, and/or enhancing the brightening thereof, which comprisestopically administering to the mammal an effective amount of one or morecompounds described herein as a melanogenesis modifier.

In a particular embodiment, a melanogenesis modifier as disclosed hereinor a composition thereof may be applied to sites of hyperpigmentationincluding, without limitation, age spots, freckles, drug-inducedhyperpigmentation, post-inflammatory hyperpigmentation as seen in acne,seborrheic keratoses, melasma and chloasma. For some individuals, bodywhitening over a larger area of the skin is desirable and may beachieved with a more generalized application of a melanogenesisinhibitor disclosed herein or a composition thereof.

In a further aspect, the disclosed embodiments provide compositions,including cosmetic formulations, comprising a compound or compoundsdisclosed herein, and a suitable biocompatible or bioinert carrier,excipient or diluent. In this aspect, the cosmetic or pharmaceuticalcomposition can comprise one or more of the compounds described herein.Moreover, the compounds disclosed herein are useful in cosmetic and/orpharmaceutical compositions and treatment methods disclosed herein, areall pharmaceutically and/or cosmetically acceptable as prepared andused.

In a further aspect, disclosed herein are compositions comprising acombination of a compound described herein with various additionalcompounds or agents, including compounds or agents that may have a likeeffect on melanogenesis, such as, for example, other skin lighteners,skin brightening agents or skin bleaching agents. In some embodiments,the additional compound or agent may be a skin care active agent, suchas an abrasive, an absorbent, an astringent, an aesthetic component,such as fragrances, pigments, colorings/colorants, essential oils, skinsensates, astringents and other aesthetic components, an antioxidant, areducing agent, a sequestrant, a skin bleaching or lightening agent, askin conditioning agent, for example humectants and emollients, a skinsoothing agent, a skin healing agent, such as pathenol and derivatives,aloe vera, pantothenic acid, allantoin, bisbolol, dipotassiumglycyrrhizinate, skin treating agents, vitamins and derivatives, such asa retinoid, or mixtures thereof. In some embodiments, the retinoid isretinol, retinal, retinol esters, retinyl propionate, retinoic acid,retinyl palmitate, or mixtures thereof. In this aspect, thepharmaceutical and/or cosmetic compositions can comprise one or more ofthe compounds described herein. Moreover, the compounds are useful inthe pharmaceutical and/or cosmetic compositions and treatment methodsdisclosed herein, are all pharmaceutically and/or cosmeticallyacceptable as prepared and used.

Also provided are methods for inhibiting melanogenesis by melanocytes,comprising administering to the melanocytes or skin tissue an effectiveamount of a plant extract containing a melanogenesis inhibitor. In someembodiments, the melanogenesis inhibitor is a benzopyran melanogenesisinhibitor as in Formula I. In some embodiments, the melanogenesisinhibitor is an osajin derivative, such as osajin-4′-methyl ether. Insome embodiments, the melanogenesis inhibitor ispomiferin-3′,4′-dimethyl ether or a pomiferin-3′,4′-dimethyl etherderivative. In some embodiments, the melanocytes are mammalianmelanocytes. In some embodiments, the skin tissue is human skinincluding but not limited to African American, Asian and Caucasian skinequivalents. In some embodiments, the plant extract is derived from aplant of the osage family. In some embodiments, the plant extract isderived from the fruit of Maclura pomifera (osage orange).

In some embodiments, also provided are plant extracts containing aprophylactically, therapeutically and/or cosmetically effective amountof a melanogenesis inhibitor for use as an inhibitor of melanogenesis.The plant extract can be used as a pharmaceutical, a medicament or as acosmetic agent. In some embodiments, the plant extract is substantiallypurified or partially purified for concentration of the melanogenesisinhibitor. In other embodiments, the plant extract may be substantiallyliquefied or partially liquefied for administration to a patient in needthereof. The plant extract may also be processed to remove particulatematter prior to administration. In some embodiments, the melanogenesisinhibitor is an osajin derivative, such as osajin-4′-methyl ether.

Also provided are uses of a plant extract as disclosed herein for themanufacture of a medicament or cosmetic agent to treat a disease,condition or effect for which a melanogenesis inhibitor is indicated.The diseases, condition or effect that can be prevented, treated,ameliorated and/or managed by the subject compositions and methodsinclude but are not limited to hyperpigmentation or uneven pigmentationdisorders such as age spots, freckles, drug-induced hyperpigmentation,post-inflammatory hyperpigmentation as seen in acne, seborrheickeratoses, melasma and chloasma. In other embodiments, a topicalformulation comprising a composition is provided for cosmetic and/ordermatological/pharmaceutical use, said composition comprising a plantextract containing a prophylactically, cosmetically or therapeuticallyeffective amount of osajin-4′-methyl ether or pomiferin-3′,4′-dimethylether. In some embodiments, the plant extract is derived from a plant ofthe osage family. In some embodiments, the plant extract is derived fromthe fruit of Maclura pomifera. In some embodiments, the plant extract issubstantially purified or partially purified for concentration of themelanogenesis inhibitor. In other embodiments, the plant extract may besubstantially liquefied or partially liquefied for administration to apatient in need thereof. The plant extract may also be processed toremove particulate matter prior to administration. In some embodiments,the melanogenesis inhibitor is an osajin derivative, such asosajin-4′-methyl ether. In some embodiments, the melanogenesis inhibitoris pomiferin-3′,4′-dimethyl ether or a pomiferin-3′,4′-dimethyl etherderivative.

Also provided are methods for preventing, treating, ameliorating ormanaging a disease or condition involving undesired or aberrantmelanogenesis, which comprises administering to a patient in need ordesirous of such prevention, treatment, amelioration or management, aprophylactically or therapeutically effective melanogenesis-inhibitingamount of a plant extract containing a melanogenesis inhibitor. In someembodiments, the melanogenesis inhibitor is a benzopyran melanogenesisinhibitor as in Formula I. In one embodiment, the melanogenesisinhibitor is an osajin derivative, such as osajin-4′-methyl ether. Insome embodiments, the melanogenesis inhibitor ispomiferin-3′,4′-dimethyl ether or a pomiferin-3′,4′-dimethyl etherderivative.

In yet another aspect, methods are provided for altering or restoringpigmentation in mammalian skin, hair, wool or fur comprisingadministering to the mammalian skin, hair, wool or fur an amount, whichis effective to alter or restore pigmentation in mammalian skin, hair,wool or fur, of a plant extract containing osajin. In still anotheraspect, also provided are methods of treatment of a mammal, including ahuman being, to treat a disease for which a melanogenesis inhibitor isindicated, including treating said mammal with an effective amount of aplant extract containing osajin. In some embodiments, the plant extractis derived from a plant of the osage family. In some embodiments, theplant extract is derived from the fruit of Maclura pomifera. In someembodiments, the plant extract is substantially purified or partiallypurified for concentration of the melanogenesis inhibitor. In otherembodiments, the plant extract may be substantially liquefied orpartially liquefied for administration to a patient in need thereof. Theplant extract may also be processed to remove particulate matter priorto administration. In some embodiments, the melanogenesis inhibitor isan osajin derivative, such as osajin-4′-methyl ether. In furtherembodiments, the melanogenesis inhibitor is pomiferin-3′,4′-dimethylether or a pomiferin-3′,4′-dimethyl ether derivative.

In some embodiments of the subject methods, the melanogenesis-inhibitorcontaining plant extract is administered to lighten or reducepigmentation levels. For example, the melanogenesis-inhibitor-containingplant extract is administered to lighten or reduce pigmentation levelsof hyperpigmented sites on skin. In some embodiments, the melanogenesisinhibitor is an osajin derivative, such as osajin-4′-methyl ether. Infurther embodiments, the melanogenesis inhibitor ispomiferin-3′,4′-dimethyl ether or a pomiferin-3′,4′-dimethyl etherderivative. In some embodiments, the plant extract is derived from aplant of the osage family. In some embodiments, the plant extract isderived from the fruit of Maclura pomifera. In some embodiments, theplant extract is substantially purified or partially purified forconcentration of the melanogenesis inhibitor. In other embodiments, theplant extract may be substantially liquefied or partially liquefied foradministration to a patient in need thereof. The plant extract may alsobe processed to remove particulate matter prior to administration. Insome embodiments, the melanogenesis inhibitor is an osajin derivative,such as osajin-4′-methyl ether. In further embodiments, themelanogenesis inhibitor is pomiferin-3′,4′-dimethyl ether or apomiferin-3′,4′-dimethyl ether derivative.

In a further embodiment, combinations of a plant extract as disclosedherein and a like-acting agent are provided. The like acting agent canbe selected from a cosmetic ingredient and/or a pharmacologically activeagent. For example, the cosmetic ingredient may be a skin lightener or asunscreen agent or an agent that increases skin cell turnover. Thepharmacologically active agent can be selected from anothermelanogenesis inhibitor.

Another aspect encompasses a method for inhibiting melanogenesis bymelanocytes comprising administering to the melanocytes an effectiveamount of a plant extract containing a melanogenesis-inhibitor incombination with a like-acting agent. In some embodiments, the plantextract is substantially purified or partially purified forconcentration of the melanogenesis inhibitor. In other embodiments, theplant extract may be substantially liquefied or partially liquefied foradministration to a patient in need thereof. The plant extract may alsobe processed to remove particulate matter prior to administration. Insome embodiments, the melanogenesis inhibitor is an osajin derivative,such as osajin-4′-methyl ether. In some embodiments, the melanogenesisinhibitor is pomiferin-3′,4′-dimethyl ether or apomiferin-3′,4′-dimethyl ether derivative.

Also provided herein is a method for preventing, treating, amelioratingor managing a disease or condition involving undesired or aberrantmelanogenesis, which comprises administering to a patient in need ordesirous of such prevention, treatment, amelioration or management, aprophylactically or therapeutically effective melanogenesis-inhibitingamount of a plant extract in combination with a like-acting agent.

In another aspect, also provided are methods of treatment of a mammal,including a human being, to treat a disease for which a melanogenesisinhibitor is indicated, including treating said mammal with an effectiveamount of a plant extract containing a melanogenesis-inhibitor incombination with a like-acting agent. In some embodiments, the plantextract is derived from a plant of the osage family. In someembodiments, the plant extract is derived from the fruit of Maclurapomifera.

In still another aspect, provided are methods for altering or restoringpigmentation in mammalian skin, hair, wool or fur comprisingadministering to the mammalian skin, hair, wool or fur an amount, whichis effective to alter or restore pigmentation in mammalian skin, hair,wool or fur, of a plant extract containing a melanogenesis-inhibitor incombination with a like-acting agent.

In any of the above subject methods, the like acting agent can beselected from a cosmetic ingredient and a pharmacologically activeagent. One example of a cosmetic ingredient is a skin lightener. Thepharmacologically active agent can be selected from anothermelanogenesis inhibitor.

Other objects and advantages will become apparent to those skilled inthe art from a consideration of the ensuing detailed description, whichproceeds with reference to the following illustrative drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph of the results of individual dose-response testing ofcompounds of the invention as inhibitors of melanogenesis.

FIG. 2 is a graph of the results of the MTT proliferation dose responsetesting of particular compounds of the invention.

FIG. 3 is a graph of the results of the individual MTT proliferationdose response testing of Osajin.

FIG. 4 is a graph of the results of the individual MTT proliferationdose response testing of Osajin-4′-methyl ether.

FIG. 5 is a graph of the results of the individual MTT proliferationdose response testing of Pomiferin.

FIG. 6 is a graph of the results of individual MTT proliferation doseresponse testing of Pomiferin-3′,4′-dimethyl ether.

FIG. 7 is a graph of the results of the individual MTT proliferationdose response testing of Warangalone.

DETAILED DESCRIPTION OF THE INVENTION Definitions

When describing the compounds, pharmaceutical and/or cosmeticcompositions containing such compounds and methods of using suchcompounds and compositions, the following terms have the followingmeanings unless otherwise indicated. It should also be understood thatany of the moieties defined forth below may be substituted with avariety of substituents, and that the respective definitions areintended to include such substituted moieties within their scope.

“Acyl” refers to a group or radical —C(O)R²⁰, where R²⁰ is hydrogen,substituted or unsubstituted alkyl, substituted or unsubstitutedcycloalkyl, substituted or unsubstituted cycloheteroalkyl, substitutedor unsubstituted aryl, substituted or unsubstituted arylalkyl,substituted or unsubstituted heteroalkyl, substituted or unsubstitutedheteroaryl, substituted or unsubstituted heteroarylalkyl as definedherein. Representative examples include, but are not limited to, formyl,acetyl, cylcohexylcarbonyl, cyclohexylmethylcarbonyl, benzoyl,benzylcarbonyl and the like.

“Acylamino” refers to a group or radical —NR²¹C(O)R²², where R²¹ ishydrogen, substituted or unsubstituted alkyl, substituted orunsubstituted cycloalkyl, substituted or unsubstituted cycloheteroalkyl,substituted or unsubstituted aryl, substituted or unsubstitutedarylalkyl, substituted or unsubstituted heteroalkyl, substituted orunsubstituted heteroaryl, substituted or unsubstituted heteroarylalkyland R²² is hydrogen, substituted or unsubstituted alkyl, substituted orunsubstituted alkoxy, substituted or unsubstituted cycloalkyl,substituted or unsubstituted cycloheteroalkyl, substituted orunsubstituted aryl, substituted or unsubstituted arylalkyl, substitutedor unsubstituted heteroalkyl, substituted or unsubstituted heteroaryl orsubstituted or unsubstituted heteroarylalkyl, as defined herein.Representative examples include, but are not limited to, formylamino,acetylamino, cyclohexylcarbonylamino, cyclohexylmethyl-carbonylamino,benzoylamino, benzylcarbonylamino and the like.

“Acyloxy” refers to the group or radical —OC(O)R²³ where R²³ ishydrogen, substituted or unsubstituted alkyl, substituted orunsubstituted aryl or substituted or unsubstituted cycloalkyl.

“Substituted alkenyl” includes those groups recited in the definition of“substituted” herein, and particularly refers to an alkenyl group having1 or more substituents, for instance from 1 to 5 substituents, andparticularly from 1 to 3 substituents, selected from the groupconsisting of acyl, acylamino, acyloxy, alkoxy, substituted alkoxy,alkoxycarbonyl, alkoxycarbonylamino, amino, substituted amino,aminocarbonyl, aminocarbonylamino, aminocarbonyloxy, aryl, aryloxy,azido, carboxyl, cyano, cycloalkyl, substituted cycloalkyl, halogen,hydroxyl, keto, nitro, thioalkoxy, substituted thioalkoxy, thioaryloxy,thioketo, thiol, alkyl-S(O)—, aryl-S(O)—, alkyl-S(O)₂— and aryl-S(O)₂—.

“Alkoxy” refers to the group —OR²⁴ where R²⁴ is alkyl. Particular alkoxygroups include, by way of example, substituted or unsubstituted methoxy,substituted or unsubstituted ethoxy, substituted or unsubstitutedn-propoxy, substituted or unsubstituted isopropoxy, substituted orunsubstituted n-butoxy, substituted or unsubstituted tert-butoxy,substituted or unsubstituted sec-butoxy, substituted or unsubstitutedn-pentoxy, substituted or unsubstituted n-hexoxy, substituted orunsubstituted 1,2-dimethylbutoxy, and the like.

“Substituted alkoxy” includes those groups recited in the definition of“substituted” herein, and particularly refers to an alkoxy group having1 or more substituents, for instance from 1 to 5 substituents, andparticularly from 1 to 3 substituents, selected from the groupconsisting of acyl, acylamino, acyloxy, alkoxy, substituted alkoxy,alkoxycarbonyl, alkoxycarbonylamino, amino, substituted amino,aminocarbonyl, aminocarbonylamino, aminocarbonyloxy, aryl, aryloxy,azido, carboxyl, cyano, cycloalkyl, substituted cycloalkyl, halogen,heteroaryl, hydroxyl, keto, nitro, thioalkoxy, substituted thioalkoxy,thioaryloxy, thioketo, thiol, alkyl-S(O)—, aryl-S(O)—, alkyl-S(O)₂— andaryl-S(O)₂—.

“Alkoxycarbonylamino” refers to the group —NR²⁵C(O)R²⁶ where R²⁵ ishydrogen, substituted or unsubstituted alkyl, substituted orunsubstituted aryl or substituted or unsubstituted cycloalkyl, and R²⁶is substituted or unsubstituted alkyl or substituted or unsubstitutedcycloalkyl.

“Alkyl” refers to monovalent saturated alkane radical groupsparticularly having up to about 11 carbon atoms, more particularly as alower alkyl, from 1 to 8 carbon atoms and still more particularly, from1 to 6 carbon atoms. The hydrocarbon chain may be eitherstraight-chained or branched. This term is exemplified by groups such asmethyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, tert-butyl,n-hexyl, n-octyl, tert-octyl and the like, and may be substituted orunsubstituted. The term “lower alkyl” refers to alkyl groups having 1 to6 carbon atoms. The term “alkyl” also includes “cycloalkyls” as definedbelow.

“Substituted alkyl” includes those groups recited in the definition of“substituted” herein, and particularly refers to an alkyl group having 1or more substituents, for instance from 1 to 5 substituents, andparticularly from 1 to 3 substituents, selected from the groupconsisting of acyl, acylamino, acyloxy, alkoxy, substituted alkoxy,alkoxycarbonyl, alkoxycarbonylamino, amino, substituted amino,aminocarbonyl, aminocarbonylamino, aminocarbonyloxy, aryl, aryloxy,azido, carboxyl, cyano, cycloalkyl, substituted cycloalkyl, halogen,hydroxyl, heteroaryl, keto, nitro, thioalkoxy, substituted thioalkoxy,thioaryloxy, thioketo, thiol, alkyl-S(O)—, aryl-S(O)—, alkyl-S(O)₂—, andaryl-S(O)₂—.

“Alkylene” refers to divalent saturated alkene radical groups having 1to 11 carbon atoms and more particularly 1 to 6 carbon atoms which canbe straight-chained or branched. This term is exemplified by groups suchas substituted or unsubstituted methylene (—CH₂—), substituted orunsubstituted ethylene (—CH₂CH₂—), the substituted or unsubstitutedpropylene isomers (e.g., —CH₂CH₂CH₂— and —CH(CH₃)CH₂—) and the like.

“Substituted alkylene” includes those groups recited in the definitionof “substituted” herein, and particularly refers to an alkylene grouphaving 1 or more substituents, for instance from 1 to 5 substituents,and particularly from 1 to 3 substituents, selected from the groupconsisting of acyl, acylamino, acyloxy, alkoxy, substituted alkoxy,alkoxycarbonyl, alkoxycarbonylamino, amino, substituted amino,aminocarbonyl, aminocarbonylamino, aminocarbonyloxy, aryl, aryloxy,azido, carboxyl, cyano, halogen, hydroxyl, keto, nitro, thioalkoxy,substituted thioalkoxy, thioaryloxy, thioketo, thiol, alkyl-S(O)—,aryl-S(O)—, alkyl-S(O)₂— and aryl-S(O)₂—.

“Alkenyl” refers to monovalent olefinically unsaturated hydrocarbylgroups preferably having 2 to 11 carbon atoms, particularly, from 2 to 8carbon atoms, and more particularly, from 2 to 6 carbon atoms, which canbe straight-chained or branched and having at least 1 and particularlyfrom 1 to 2 sites of olefinic unsaturation. Particular alkenyl groupsinclude substituted or unsubstituted ethenyl (—CH═CH₂), substituted orunsubstituted n-propenyl (—CH₂CH═CH₂), substituted or unsubstitutedisopropenyl (—C(CH₃)═CH₂), substituted or unsubstituted vinyl andsubstituted vinyl, and the like.

“Alkenylene” refers to divalent olefinically unsaturated hydrocarbylgroups particularly having up to about 11 carbon atoms and moreparticularly 2 to 6 carbon atoms which can be straight-chained orbranched and having at least 1 and particularly from 1 to 2 sites ofolefinic unsaturation. This term is exemplified by groups such assubstituted or unsubstituted ethenylene (—CH═CH—), substituted orunsubstituted propenylene isomers (e.g., —CH═CHCH₂— and —C(CH₃)═CH— and—CH═C(CH₃)—) and the like.

“Alkynyl” refers to acetylenically or alkynically unsaturatedhydrocarbyl groups particularly having 2 to 11 carbon atoms and moreparticularly 2 to 6 carbon atoms which can be straight-chained orbranched and having at least 1 and particularly from 1 to 2 sites ofalkynyl unsaturation. Particular non-limiting examples of alkynyl groupsinclude substituted or unsubstituted acetylenic, substituted orunsubstituted ethynyl (—C≡CH), substituted or unsubstituted propargyl(—CH₂C≡CH), and the like.

“Substituted alkynyl” includes those groups recited in the definition of“substituted” herein, and particularly refers to an alkynyl group having1 or more substituents, for instance from 1 to 5 substituents, andparticularly from 1 to 3 substituents, selected from the groupconsisting of acyl, acylamino, acyloxy, alkoxy, substituted alkoxy,alkoxycarbonyl, alkoxycarbonylamino, amino, substituted amino,aminocarbonyl, aminocarbonylamino, aminocarbonyloxy, aryl, aryloxy,azido, carboxyl, cyano, cycloalkyl, substituted cycloalkyl, halogen,hydroxyl, keto, nitro, thioalkoxy, substituted thioalkoxy, thioaryloxy,thioketo, thiol, alkyl-S(O)—, aryl-S(O)—, alkyl-S(O)₂— and aryl-S(O)₂—.

“Alkanoyl” or “acyl” as used herein refers to the group R²⁷—C(O)—, whereR²⁷ is hydrogen or substituted or unsubstituted alkyl as defined above.

“Aryl” refers to a monovalent aromatic hydrocarbon group derived by theremoval of one hydrogen atom from a single carbon atom of a parentaromatic ring system. Typical aryl groups include, but are not limitedto, groups derived from aceanthrylene, acenaphthylene,acephenanthrylene, anthracene, azulene, benzene, chrysene, coronene,fluoranthene, fluorene, hexacene, hexaphene, hexylene, as-indacene,s-indacene, indane, indene, naphthalene, octacene, octaphene, octalene,ovalene, penta-2,4-diene, pentacene, pentalene, pentaphene, perylene,phenalene, phenanthrene, picene, pleiadene, pyrene, pyranthrene,rubicene, triphenylene, trinaphthalene and the like, and may besubstituted or unsubstituted. Particularly, an aryl group comprises from6 to 14 carbon atoms.

“Substituted Aryl” includes those groups recited in the definition of“substituted” herein, and particularly refers to an aryl group that mayoptionally be substituted with 1 or more substituents, for instance from1 to 5 substituents, particularly 1 to 3 substituents, selected from thegroup consisting of acyl, acylamino, acyloxy, alkenyl, substitutedalkenyl, alkoxy, substituted alkoxy, alkoxycarbonyl, alkyl, substitutedalkyl, alkynyl, substituted alkynyl, amino, substituted amino,aminocarbonyl, aminocarbonylamino, aminocarbonyloxy, aryl, aryloxy,azido, carboxyl, cyano, cycloalkyl, substituted cycloalkyl, halogen,hydroxyl, nitro, thioalkoxy, substituted thioalkoxy, thioaryloxy, thiol,alkyl-S(O)—, aryl-S(O)—, alkyl-S(O)₂— and aryl-S(O)₂—.

“Fused Aryl” refers to an aryl having two of its ring carbon in commonwith a second substituted or unsubstituted aryl ring or with asubstituted or unsubstituted aliphatic ring.

“Alkaryl” refers to an aryl group, as defined above, substituted withone or more substituted or unsubstituted alkyl groups, as defined above.

“Aralkyl” or “arylalkyl” refers to an alkyl group, as defined above,substituted with one or more substituted or unsubstituted aryl groups,as defined above.

“Aryloxy” refers to substituted or unsubstituted —O-aryl groups wherein“aryl” is as defined above.

“Alkylamino” refers to the group alkyl-NR²⁸R²⁹, each of R²⁸ and R²⁹ areindependently selected from hydrogen and substituted or unsubstitutedalkyl.

“Arylamino” refers to the group aryl-NR³⁰R³¹, wherein each of R³⁰ andR³¹ are independently selected from hydrogen, substituted orunsubstituted aryl and substituted or unsubstituted heteroaryl.

“Alkoxyamino” refers to a radical —N(H)OR³² where R³² represents asubstituted or unsubstituted alkyl or substituted or unsubstitutedcycloalkyl group as defined herein.

“Alkoxycarbonyl” refers to a substituted or unsubstituted radical—C(O)-alkoxy where alkoxy is as defined herein.

“Alkylarylamino” refers to a substituted or unsubstituted radical—NR³³R³⁴ where R³³ represents an alkyl or cycloalkyl group and R³⁴ is anaryl as defined herein.

“Alkylsulfonyl” refers to a substituted or unsubstituted radical—S(O)₂R³⁵ where R³⁵ is an alkyl or cycloalkyl group as defined herein.Representative examples include, but are not limited to, methylsulfonyl,ethylsulfonyl, propylsulfonyl, butylsulfonyl and the like.

“Alkylsulfinyl” refers to a substituted or unsubstituted radical—S(O)R³⁵ where R³⁵ is an alkyl or cycloalkyl group as defined herein.Representative examples include, but are not limited to, methylsulfinyl,ethylsulfinyl, propylsulfinyl, butylsulfinyl and the like.

“Alkylthio” refers to a substituted or unsubstituted radical —SR³⁵ whereR³⁵ is an alkyl or cycloalkyl group as defined herein that may beoptionally substituted as defined herein. Representative examplesinclude, but are not limited to, methylthio, ethylthio, propylthio,butylthio, and the like.

“Amino” refers to the radical —NH₂.

“Substituted amino” includes those groups recited in the definition of“substituted” herein, and particularly refers to the group —N(R³⁶)₂where each R³⁶ is independently selected from the group consisting ofhydrogen, alkyl, substituted alkyl, alkenyl, substituted alkenyl,alkynyl, substituted alkynyl, aryl, cycloalkyl, substituted cycloalkyl,and where both R groups are joined to form an alkylene group. When bothR groups are hydrogen, —N(R³⁶)₂ is an amino group.

“Aminocarbonyl” refers to the group —C(O)NR³⁷R³⁷ where each R³⁷ isindependently hydrogen, substituted or unsubstituted alkyl, substitutedor unsubstituted aryl and substituted or unsubstituted cycloalkyl, orwhere the R³⁷ groups are joined to form an alkylene group.

“Aminocarbonylamino” refers to the group —NR³⁸C(O)NR³⁸R³⁸ where each R³⁸is independently hydrogen, substituted or unsubstituted alkyl,substituted or unsubstituted aryl or substituted or unsubstitutedcycloalkyl, or where two R groups are joined to form an alkylene group.

“Aminocarbonyloxy” refers to the group —OC(O)NR³⁹R³⁹ where each R³⁹ isindependently hydrogen, substituted or unsubstituted alkyl, substitutedor unsubstituted aryl or substituted or unsubstituted cycloalkyl, orwhere the R groups are joined to form an alkylene group.

“Arylalkyloxy” refers to a substituted or unsubstituted —O-arylalkylradical where arylalkyl is as defined herein.

“Arylamino” means a substituted or unsubstituted radical —NHR⁴⁰ whereR⁴⁰ represents an aryl group as defined herein.

“Aryloxycarbonyl” refers to a substituted or unsubstituted radical—C(O)—O-aryl where aryl is as defined herein.

“Arylsulfonyl” refers to a r substituted or unsubstituted radical—S(O)₂R⁴¹ where R⁴¹ is an aryl or heteroaryl group as defined herein.

“Azido” refers to the radical —N₃.

“Bicycloaryl” refers to a monovalent aromatic hydrocarbon group derivedby the removal of one hydrogen atom from a single carbon atom of aparent bicycloaromatic ring system. Typical bicycloaryl groups include,but are not limited to, groups derived from indane, indene, naphthalene,tetrahydronaphthalene, and the like, and may be substituted orunsubstituted. Particularly, an aryl group comprises from 8 to 11 carbonatoms.

“Bicycloheteroaryl” refers to a monovalent bicycloheteroaromatic groupderived by the removal of one hydrogen atom from a single atom of aparent bicycloheteroaromatic ring system. Typical bicycloheteroarylgroups include, but are not limited to, groups derived from benzofuran,benzimidazole, benzindazole, benzdioxane, chromene, chromane, cinnoline,phthalazine, indole, indoline, indolizine, isobenzofuran, isochromene,isoindole, isoindoline, isoquinoline, benzothiazole, benzoxazole,naphthyridine, benzoxadiazole, pteridine, purine, benzopyran,benzpyrazine, pyridopyrimidine, quinazoline, quinoline, quinolizine,quinoxaline, benzomorphan, tetrahydroisoquinoline, tetrahydroquinoline,and the like, and may be substituted or unsubstituted. Preferably, thebicycloheteroaryl group is between 9-11 membered bicycloheteroaryl, with5-10 membered heteroaryl being particularly preferred. Particularbicycloheteroaryl groups are those derived from benzothiophene,benzofuran, benzothiazole, indole, quinoline, isoquinoline,benzimidazole, benzoxazole and benzdioxane.

“Carbamoyl” refers to the radical —C(O)N(R⁴²)₂ where each R⁴² group isindependently hydrogen, substituted or unsubstituted alkyl, substitutedor unsubstituted cycloalkyl or substituted or unsubstituted aryl, asdefined herein, which may be optionally substituted as defined herein.

“Carboxy” refers to the radical —C(O)OH.

“Carboxyamino” refers to the radical —N(H)C(O)OH.

“Cycloalkyl” refers to cyclic hydrocarbyl groups having from 3 to about10 carbon atoms and having a single cyclic ring or multiple condensedrings, including fused and bridged ring systems, which optionally can besubstituted with from 1 to 3 alkyl groups. Such cycloalkyl groupsinclude, by way of example, single ring structures such as cyclopropyl,cyclobutyl, cyclopentyl, cyclooctyl, 1-methylcyclopropyl,2-methylcyclopentyl, 2-methylcyclooctyl, and the like, and multiple ringstructures such as adamantanyl, and the like, and may be substituted orunsubstituted.

“Substituted cycloalkyl” includes those groups recited in the definitionof “substituted” herein, and particularly refers to a cycloalkyl grouphaving 1 or more substituents, for instance from 1 to 5 substituents,and particularly from 1 to 3 substituents, selected from the groupconsisting of acyl, acylamino, acyloxy, alkoxy, substituted alkoxy,alkoxycarbonyl, alkoxycarbonylamino, amino, substituted amino,aminocarbonyl, aminocarbonylamino, aminocarbonyloxy, aryl, aryloxy,azido, carboxyl, cyano, cycloalkyl, substituted cycloalkyl, halogen,hydroxyl, keto, nitro, thioalkoxy, substituted thioalkoxy, thioaryloxy,thioketo, thiol, alkyl-S(O)—, aryl-S(O)—, alkyl-S(O)₂— and aryl-S(O)₂—.

“Cycloalkoxy” refers to the group —OR⁴³ where R⁴³ is substituted orunsubstituted cycloalkyl. Such cycloalkoxy groups include, by way ofexample, substituted or unsubstituted cyclopentoxy, substituted orunsubstituted cyclohexoxy and the like.

“Cycloalkenyl” refers to cyclic hydrocarbyl groups having from 3 to 10carbon atoms and having a single cyclic ring or multiple condensedrings, including fused and bridged ring systems and having at least oneand particularly from 1 to 2 sites of olefinic unsaturation. Suchcycloalkenyl groups include, by way of example, single ring structuressuch as substituted or unsubstituted cyclohexenyl, substituted orunsubstituted cyclopentenyl, substituted or unsubstituted cyclopropenyl,and the like.

“Substituted cycloalkenyl” includes those groups recited in thedefinition of “substituted” herein, and particularly refers to acycloalkenyl group having 1 or more substituents, for instance from 1 to5 substituents, and particularly from 1 to 3 substituents, selected fromthe group consisting of acyl, acylamino, acyloxy, alkoxy, substitutedalkoxy, alkoxycarbonyl, alkoxycarbonylamino, amino, substituted amino,aminocarbonyl, aminocarbonylamino, aminocarbonyloxy, aryl, aryloxy,azido, carboxyl, cyano, cycloalkyl, substituted cycloalkyl, halogen,hydroxyl, keto, nitro, thioalkoxy, substituted thioalkoxy, thioaryloxy,thioketo, thiol, alkyl-S(O)—, aryl-S(O)—, alkyl-S(O)₂— and aryl-S(O)₂—.

“Fused Cycloalkenyl” refers to a substituted or unsubstitutedcycloalkenyl having two of its ring carbon atoms in common with a secondaliphatic or aromatic ring and having its olefinic unsaturation locatedto impart aromaticity to the cycloalkenyl ring.

“Cyanato” refers to the radical —OCN.

“Cyano” refers to the radical —CN.

“Dialkylamino” means a radical —NR⁴⁴R⁴⁵ where R⁴⁴ and R⁴⁵ independentlyrepresent an alkyl, substituted alkyl, aryl, substituted aryl,cycloalkyl, substituted cycloalkyl, cycloheteroalkyl, substitutedcycloheteroalkyl, heteroaryl, or substituted heteroaryl group as definedherein.

“Ethenyl” refers to substituted or unsubstituted —(C═C)—.

“Ethylene” refers to substituted or unsubstituted —(C—C)—.

“Ethynyl” refers to —(C≡C)—.

“Halo” or “halogen” refers to fluoro, chloro, bromo and iodo. Preferredhalo groups are either fluoro or chloro.

“Hydroxy” refers to the radical —OH.

“Nitro” refers to the radical —NO₂.

“Substituted” refers to a group in which one or more hydrogen atoms areeach independently replaced with the same or different substituent(s).Typical substituents include, but are not limited to, —X, —R⁴⁶, —O⁻, ═O,—OR⁴⁶, —SR⁴⁶, —S⁻, ═S, —NR⁴⁶R⁴⁷, ═NR⁴⁶, —CS₃, —CF₃, —CN, —OCN, —SCN,—NO, —NO₂, ═N₂, —N₃, —S(O)₂O⁻, —S(O)₂OH, —S(O)₂R⁴⁶, —OS(O₂)O⁻,—OS(O)₂R⁴⁶, —P(O)(O⁻)₂, —P(O)(OR⁴⁶)(O⁻), —OP(O)(OR⁴⁶)(OR⁴⁷), —C(O)R⁴⁶,—C(S)R⁴⁶, —C(O)OR⁴⁶, —C(O)NR⁴⁶R⁴⁷, —C(O)O⁻, —C(S)OR⁴⁶, —NR⁴⁸C(O)NR⁴⁶R⁴⁷,—NR⁴⁸C(S)NR⁴⁶R⁴⁷, —NR⁴⁹C(NR⁴⁸)NR⁴⁶R⁴⁷ and —C(NR⁴⁸)NR⁴⁶R⁴⁷, where each Xis independently a halogen; each R⁴⁶, R⁴⁷, R⁴⁸ and R⁴⁹ are independentlyhydrogen, alkyl, substituted alkyl, aryl, substituted alkyl, arylalkyl,substituted alkyl, cycloalkyl, substituted alkyl, cycloheteroalkyl,substituted cycloheteroalkyl, heteroalkyl, substituted heteroalkyl,heteroaryl, substituted heteroaryl, heteroarylalkyl, substitutedheteroarylalkyl, —NR⁵⁰R⁵¹, —C(O)R⁵⁰ or —S(O)₂R⁵⁰ or optionally R⁵⁰ andR⁵¹ together with the atom to which they are both attached form acycloheteroalkyl or substituted cycloheteroalkyl ring; and R⁵⁰ and R⁵¹are independently hydrogen, alkyl, substituted alkyl, aryl, substitutedalkyl, arylalkyl, substituted alkyl, cycloalkyl, substituted alkyl,cycloheteroalkyl, substituted cycloheteroalkyl, heteroalkyl, substitutedheteroalkyl, heteroaryl, substituted heteroaryl, heteroarylalkyl orsubstituted heteroarylalkyl.

Examples of representative substituted aryls include the following

In these formulae one of R⁵² and R⁵³ may be hydrogen and at least one ofR⁵² and R⁵³ is each independently selected from alkyl, alkenyl, alkynyl,cycloheteroalkyl, alkanoyl, alkoxy, aryloxy, heteroaryloxy, alkylamino,arylamino, heteroarylamino, NR⁵⁴COR⁵⁵, NR⁵⁴SOR⁵⁵, NR⁵⁴SO₂R⁵⁷, COOalkyl,COOaryl, CONR⁵⁴R⁵⁵, CONR⁵⁴OR⁵⁵, NR⁵⁴R⁵⁵, SO₂NR⁵⁴R⁵⁵, S-alkyl, S-alkyl,SOalkyl, SO₂alkyl, Saryl, SOaryl, SO₂aryl; or R⁵² and R⁵³ may be joinedto form a cyclic ring (saturated or unsaturated) from 5 to 8 atoms,optionally containing one or more heteroatoms selected from the group N,O or S. R⁵⁴, R⁵⁵, and R⁵⁶ are independently hydrogen, alkyl, alkenyl,alkynyl, perfluoroalkyl, cycloalkyl, cycloheteroalkyl, aryl, substitutedaryl, heteroaryl, substituted or hetero alkyl or the like.

“Hetero” when used to describe a compound or a group present on acompound means that one or more carbon atoms in the compound or grouphave been replaced by a nitrogen, oxygen, or sulfur heteroatom. Heteromay be applied to any of the hydrocarbyl groups described above such asalkyl, e.g. heteroalkyl, cycloalkyl, e.g. cycloheteroalkyl, aryl, e.g.heteroaryl, cycloalkenyl, cycloheteroalkenyl, and the like having from 1to 5, and especially from 1 to 3 heteroatoms.

“Heteroaryl” refers to a monovalent heteroaromatic group derived by theremoval of one hydrogen atom from a single atom of a parentheteroaromatic ring system. Typical heteroaryl groups include, but arenot limited to, groups derived from acridine, arsindole, carbazole,β-carboline, chromane, chromene, cinnoline, furan, imidazole, indazole,indole, indoline, indolizine, isobenzofuran, isochromene, isoindole,isoindoline, isoquinoline, isothiazole, isoxazole, naphthyridine,oxadiazole, oxazole, perimidine, phenanthridine, phenanthroline,phenazine, phthalazine, pteridine, purine, pyran, pyrazine, pyrazole,pyridazine, pyridine, pyrimidine, pyrrole, pyrrolizine, quinazoline,quinoline, quinolizine, quinoxaline, tetrazole, thiadiazole, thiazole,thiophene, triazole, xanthene, and the like. Preferably, the heteroarylgroup is between 5-15 membered heteroaryl, with 5-10 membered heteroarylbeing particularly preferred. Particular heteroaryl groups are thosederived from thiophene, pyrrole, benzothiophene, benzofuran, indole,pyridine, quinoline, imidazole, oxazole and pyrazine.

Examples of representative heteroaryls include the following:

wherein each Y is selected from carbonyl, N, NR⁵⁸, O, and S; and R⁵⁸ isindependently hydrogen, alkyl, cycloalkyl, cycloheteroalkyl, aryl,heteroaryl, heteroalkyl or the like.

As used herein, the term “cycloheteroalkyl” refers to a stableheterocyclic non-aromatic ring and fused rings containing one or moreheteroatoms independently selected from N, O and S. A fused heterocyclicring system may include carbocyclic rings and need only include oneheterocyclic ring. Examples of heterocyclic rings include, but are notlimited to, piperazinyl, homopiperazinyl, piperidinyl and morpholinyl,and are shown in the following illustrative examples:

wherein each X is selected from CR⁵⁸, CR⁵⁸ ₂, NR⁵⁸, O and S; and each Yis selected from NR⁵⁸, O and S; and R⁵⁸ is independently hydrogen,alkyl, cycloalkyl, cycloheteroalkyl, aryl, heteroaryl, heteroalkyl orthe like. These cycloheteroalkyl rings may be optionally substitutedwith one or more groups selected from the group consisting of acyl,acylamino, acyloxy, alkoxy, substituted alkoxy, alkoxycarbonyl,alkoxycarbonylamino, amino, substituted amino, aminocarbonyl,aminocarbonylamino, aminocarbonyloxy, aryl, aryloxy, azido, carboxyl,cyano, cycloalkyl, substituted cycloalkyl, halogen, hydroxyl, keto,nitro, thioalkoxy, substituted thioalkoxy, thioaryloxy, thioketo, thiol,alkyl-S(O)—, aryl-S(O)—, alkyl-S(O)₂— and aryl-S(O)₂—. Substitutinggroups include carbonyl or thiocarbonyl which provide, for example,lactam and urea derivatives.

Examples of representative cycloheteroalkenyls include the following:

wherein each X is selected from CR⁵⁸, CR⁵⁸ ₂, NR⁵⁸, O and S; and each Yis selected from carbonyl, N, NR⁵⁸, O and S; and R⁵⁸ is independentlyhydrogen, alkyl, cycloalkyl, cycloheteroalkyl, aryl, heteroaryl,heteroalkyl or the like.

Examples of representative aryl having hetero atoms containingsubstitution include the following:

wherein each X is selected from CR⁵⁸ ₂, NR⁵⁸, O and S; and each Y isselected from carbonyl, NR⁵⁸, O and S; and R⁵⁸ is independentlyhydrogen, alkyl, cycloalkyl, cycloheteroalkyl, aryl, heteroaryl,heteroalkyl or the like.

“Hetero substituent” refers to a halo, O, S or N atom-containingfunctionality that may be present as an R⁴ in a R⁴C group present assubstituents directly on the ring or rings of the compounds disclosedherein, or that may be present as a substituent in any “substituted”aryl and aliphatic groups present in the compounds.

Examples of hetero substituents include:

-halo,

—NO₂, —NH₂, —NHR⁵⁹, —N(R⁵⁹)₂,

—NRCOR, —NR⁵⁹SOR⁵⁹, —NR⁵⁹SO₂R⁵⁹, OH, CN,

—CO₂H,

—R⁵⁹—OH, —O—R⁵⁹, —COOR⁵⁹,

—CON(R⁵⁹)₂, —CONROR⁵⁹,

—SO₃H, —R⁵⁹—S, —SO₂N(R⁵⁹)₂)

—S(O)R⁵⁹, —S(O)₂R⁵⁹

wherein each R⁵⁹ is independently an aryl or aliphatic, optionally withsubstitution. Among hetero substituents containing R⁵⁹ groups,preference is given to those materials having aryl and alkyl R⁵⁹ groupsas defined herein. Preferred hetero substituents are those listed above.

“Dihydroxyphosphoryl” refers to the substituted or unsubstituted radical—PO(OH)₂.

“Substituted dihydroxyphosphoryl” includes those groups recited in thedefinition of “substituted” herein, and particularly refers to adihydroxyphosphoryl radical wherein one or both of the hydroxyl groupsare substituted. Suitable substituents are described in detail below.

“Aminohydroxyphosphoryl” refers to the substituted or unsubstitutedradical —PO(OH)NH₂.

“Substituted aminohydroxyphosphoryl” includes those groups recited inthe definition of “substituted” herein, and particularly refers to anaminohydroxyphosphoryl wherein the amino group is substituted with oneor two substituents. Suitable substituents are described in detailbelow. In certain embodiments, the hydroxyl group can also besubstituted.

“Thioalkoxy” refers to the substituted or unsubstituted group —SR⁶⁰where R⁶ is alkyl.

“Substituted thioalkoxy” includes those groups recited in the definitionof “substituted” herein, and particularly refers to a thioalkoxy grouphaving 1 or more substituents, for instance from 1 to 5 substituents,and particularly from 1 to 3 substituents, selected from the groupconsisting of acyl, acylamino, acyloxy, alkoxy, substituted alkoxy,alkoxycarbonyl, alkoxycarbonylamino, amino, substituted amino,aminocarbonyl, aminocarbonylamino, aminocarbonyloxy, aryl, aryloxy,azido, carboxyl, cyano, cycloalkyl, substituted cycloalkyl, halogen,hydroxyl, keto, nitro, thioalkoxy, substituted thioalkoxy, thioaryloxy,thioketo, thiol, alkyl-S(O)—, aryl-S(O)—, alkyl-S(O)₂— and aryl-S(O)₂—.

“Sulfanyl” refers to the substituted or unsubstituted radical HS—.“Substituted sulfanyl” refers to a radical such as RS— wherein R is anysubstituent described herein.

“Sulfonyl” refers to the divalent substituted or unsubstituted radical—S(O₂)—.

“Substituted sulfonyl” refers to a radical such as R⁶¹—(O₂)S— whereinR⁶¹ is any substituent described herein. “Aminosulfonyl” or“Sulfonamide” refers to the radical H₂N(O₂)S—, and “substitutedaminosulfonyl” “substituted sulfonamide” refers to a radical such as R⁶²₂N(O₂)S— wherein each R⁶² is independently any substituent describedherein.

“Sulfone” refers to the substituted or unsubstituted group —SO₂R⁶³. Inparticular embodiments, R⁶³ is selected from H, lower alkyl, alkyl, aryland heteroaryl.

“Thioaryloxy” refers to the substituted or unsubstituted group —SR⁶⁴where R⁶⁴ is aryl.

“Thioketo” refers to the group ═S.

“Thiol” refers to the group —SH.

One having ordinary skill in the art of organic synthesis will recognizethat the maximum number of heteroatoms in a stable, chemically feasibleheterocyclic ring, whether it is aromatic or non aromatic, is determinedby the size of the ring, the degree of unsaturation and the valence ofthe heteroatoms. In general, a heterocyclic ring may have one to fourheteroatoms so long as the heteroaromatic ring is chemically feasibleand stable.

As used in this specification and the appended claims, the singularforms “a”, “an”, and “the” include plural references unless the contextclearly dictates otherwise. Thus for example, reference to “the method”includes one or more methods, and/or steps of the type described hereinand/or which will become apparent to those persons skilled in the artupon reading this disclosure.

As used herein, “mammal” refers to any member of the higher vertebrateanimals comprising the class Mammalia, which includes, but is notlimited to, humans.

As used herein, the term “melanogenesis inhibitor” is used to describe acompound identified herein as possessing the ability to inhibitmelanogenesis in a melanocyte.

As used herein, an “amount effective” shall mean an amount sufficient tocover the region of skin, hair, fur, or wool surface where a change inpigmentation is desired.

“Pharmaceutically acceptable” means approved by a regulatory agency ofthe Federal or a state government or listed in the U.S. Pharmacopoeia orother generally recognized pharmacopoeia for use in animals, and moreparticularly in humans.

“Cosmeceutically acceptable” means suitable for cosmetic applications,including topical application of the compositions disclosed herein inthe absence of significant adverse side effects upon application of thecomposition or compounds disclosed herein. Other applications includeskin care applications, including but not limited to lotions, cream,cleansing creams or lotions, soaps and other cleansers, antiperspirantand/or deodorants, makeup products, such as face powders, foundations,rouge, eye shadow, mascara, eyeliner or lipstick, sun protectionproducts, such as sunscreen or other UV-protective cosmetics, lotions orcreams, hairdressing products, such as shampoo, rinses, or treatmentsetting agents. The phrases “pharmaceutically acceptable” and“cosmeceutically acceptable” are not meant to imply mutual exclusivenessin all applications. In some embodiments, a composition may be both“pharmaceutically acceptable” and “cosmeceutically acceptable,”dependent upon the need and course of action of the compositionsdisclosed herein.

“Pharmaceutically acceptable salt” refers to a salt of a compounddisclosed herein that is pharmaceutically acceptable and that possessesthe desired pharmacological activity of the parent compound. Such saltsinclude: (1) acid addition salts, formed with inorganic acids such ashydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid,phosphoric acid, and the like; or formed with organic acids such asacetic acid, propionic acid, hexanoic acid, cyclopentanepropionic acid,glycolic acid, pyruvic acid, lactic acid, malonic acid, succinic acid,malic acid, maleic acid, fumaric acid, tartaric acid, citric acid,benzoic acid, 3-(4-hydroxybenzoyl)benzoic acid, cinnamic acid, mandelicacid, methanesulfonic acid, ethanesulfonic acid, 1,2-ethane-disulfonicacid, 2-hydroxyethanesulfonic acid, benzenesulfonic acid,4-chlorobenzenesulfonic acid, 2-naphthalenesulfonic acid,4-toluenesulfonic acid, camphorsulfonic acid,4-methylbicyclo[2.2.2]-oct-2-ene-1-carboxylic acid, glucoheptonic acid,3-phenylpropionic acid, trimethylacetic acid, tertiary butylacetic acid,lauryl sulfuric acid, gluconic acid, glutamic acid, hydroxynaphthoicacid, salicylic acid, stearic acid, muconic acid, and the like; or (2)salts formed when an acidic proton present in the parent compound eitheris replaced by a metal ion, e.g., an alkali metal ion, an alkaline earthion, or an aluminum ion; or coordinates with an organic base such asethanolamine, diethanolamine, triethanolamine, N-methylglucamine and thelike. Salts further include, by way of example only, sodium, potassium,calcium, magnesium, ammonium, tetraalkylammonium, and the like; and whenthe compound contains a basic functionality, salts of non toxic organicor inorganic acids, such as hydrochloride, hydrobromide, tartrate,mesylate, acetate, maleate, oxalate and the like. In some embodiments, a“pharmaceutically acceptable salt” may also be used in conjunction withcosmeceutically-acceptable compositions.

The term “pharmaceutically acceptable cation” refers to a non toxic,acceptable cationic counter-ion of an acidic functional group. Suchcations are exemplified by sodium, potassium, calcium, magnesium,ammonium, tetraalkylammonium cations, and the like. In some embodiments,a “pharmaceutically acceptable cation” may also be used in conjunctionwith cosmeceutically-acceptable compositions.

“Pharmaceutically acceptable vehicle” refers to a diluent, adjuvant,excipient or carrier with which a disclosed compound is administered. Insome embodiments, a “pharmaceutically acceptable vehicle” may also beused in conjunction with cosmeceutically-acceptable compositions.

“Preventing” or “prevention” refers to a reduction in risk of acquiringa disease or disorder (i.e., causing at least one of the clinicalsymptoms of the disease not to develop in a subject that may be exposedto or predisposed to the disease but does not yet experience or displaysymptoms of the disease).

“Prodrugs” refers to compounds, including derivatives of disclosedcompounds, which have cleavable groups and become by solvolysis or underphysiological conditions of compounds which are pharmaceutically activein vivo. Such examples include, but are not limited to, choline esterderivatives and the like, N-alkylmorpholine esters and the like.

“Solvate” refers to forms of the compound that are associated with asolvent, usually by a solvolysis reaction. Conventional solvents includewater, ethanol, acetic acid and the like. The compounds disclosed hereinmay be prepared e.g. in crystalline form and may be solvated orhydrated. Suitable solvates include pharmaceutically acceptablesolvates, such as hydrates, and further include both stoichiometricsolvates and non-stoichiometric solvates.

“Subject” includes humans. The terms “human,” “patient” and “subject”are used interchangeably herein.

“Therapeutically effective amount” means the amount of a compound that,when administered to a subject for treating a disease, is sufficient toeffect such treatment for the disease. The “therapeutically effectiveamount” can vary depending on the compound, the disease and itsseverity, and the age, weight, etc., of the subject to be treated.

“Treating” or “treatment” of any disease or disorder refers, in oneembodiment, to ameliorating the disease or disorder (i.e., arresting orreducing the development of the disease or at least one of the clinicalsymptoms thereof). In another embodiment “treating” or “treatment”refers to ameliorating at least one physical parameter, which may not bediscernible by the subject. In yet another embodiment, “treating” or“treatment” refers to modulating the disease or disorder, eitherphysically, (e.g., stabilization of a discernible symptom),physiologically, (e.g., stabilization of a physical parameter), or both.In yet another embodiment, “treating” or “treatment” refers to delayingthe onset of the disease or disorder, or even preventing the same. In astill further embodiment, “treating” or “treatment” refers toadministration of the compound or compositions disclosed herein forcosmetic purposes.

Other derivatives of the disclosed compounds have activity in both theiracid and acid derivative forms, but in the acid sensitive form oftenoffers advantages of solubility, tissue compatibility, or delayedrelease in the mammalian organism (see, Bundgard, H., Design ofProdrugs, pp. 7-9, 21-24, Elsevier, Amsterdam 1985). Prodrugs includeacid derivatives such as, for example, esters prepared by reaction ofthe parent acid with a suitable alcohol, or amides prepared by reactionof the parent acid compound with a substituted or unsubstituted amine,or acid anhydrides, or mixed anhydrides. Simple aliphatic or aromaticesters, amides and anhydrides derived from acidic groups pendant on thedisclosed compounds are preferred prodrugs. In some cases it isdesirable to prepare double ester type prodrugs such as (acyloxy)alkylesters or ((alkoxycarbonyl)oxy)alkylesters. Preferred are the C₁ to C₈alkyl, C₂-C₈ alkenyl, aryl, C₇-C₁₂ substituted aryl, and C₇-C₁₂arylalkyl esters of the disclosed compounds herein.

As used herein, the term “isotopic variant” refers to a compound thatcontains unnatural proportions of isotopes at one or more of the atomsthat constitute such compound. For example, an “isotopic variant” of acompound can contain one or more non-radioactive isotopes, such as forexample, deuterium (²H or D), carbon-13 (¹³C), nitrogen-15 (¹⁵N), or thelike. It will be understood that, in a compound where such isotopicsubstitution is made, the following atoms, where present, may vary, sothat for example, any hydrogen may be ²H/D, any carbon may be ¹³C, orany nitrogen may be ¹⁵N, and that the presence and placement of suchatoms may be determined within the skill of the art. Likewise, thedisclosed compounds may include the preparation of isotopic variantswith radioisotopes, in the instance for example, where the resultingcompounds may be used for drug and/or substrate tissue distributionstudies. The radioactive isotopes tritium, i.e. ³H, and carbon-14, i.e.¹⁴C, are particularly useful for this purpose in view of their ease ofincorporation and ready means of detection. Further, compounds may beprepared that are substituted with positron emitting isotopes, such as¹¹C, ¹⁸F, ¹⁵ O and ¹³N, and would be useful in Positron EmissionTopography (PET) studies for examining substrate receptor occupancy.

All isotopic variants of the compounds provided herein, radioactive ornot, are intended to be encompassed within the scope of the contemplatedcompounds.

It is also to be understood that compounds that have the same molecularformula but differ in the nature or sequence of bonding of their atomsor the arrangement of their atoms in space are termed “isomers”. Isomersthat differ in the arrangement of their atoms in space are termed“stereoisomers”.

Stereoisomers that are not mirror images of one another are termed“diastereomers” and those that are non-superimposable mirror images ofeach other are termed “enantiomers”. When a compound has an asymmetriccenter, for example, it is bonded to four different groups, a pair ofenantiomers is possible. An enantiomer can be characterized by theabsolute configuration of its asymmetric center and is described by theR- and S-sequencing rules of Cahn and Prelog, or by the manner in whichthe molecule rotates the plane of polarized light and designated asdextrorotatory or levorotatory (i.e., as (+) or (−)-isomersrespectively). A chiral compound can exist as either individualenantiomer or as a mixture thereof. A mixture containing equalproportions of the enantiomers is called a “racemic mixture”.

“Tautomers” refer to compounds that are interchangeable forms of aparticular compound structure, and that vary in the displacement ofhydrogen atoms and electrons. Thus, two structures may be in equilibriumthrough the movement of π electrons and an atom (usually H). Forexample, enols and ketones are tautomers because they are rapidlyinterconverted by treatment with either acid or base. Another example oftautomerism is the aci- and nitro- forms of phenylnitromethane, that arelikewise formed by treatment with acid or base.

Tautomeric forms may be relevant to the attainment of the optimalchemical reactivity and biological activity of a compound of interest.

The disclosed compounds may possess one or more asymmetric centers; suchcompounds can therefore be produced as individual (R)- or (S)-stereoisomers or as mixtures thereof. Unless indicated otherwise, thedescription or naming of a particular compound in the specification andclaims is intended to include both individual enantiomers and mixtures,racemic or otherwise, thereof. The methods for the determination ofstereochemistry and the separation of stereoisomers are well-known inthe art.

The Compounds

As described herein, disclosed are embodiments relating to theidentification of compounds that control melanin synthesis(melanogenesis), and the use of such compounds and compositions thereofto modify (e.g., inhibit) melanin production. Also related are methodsfor preventing and/or treating conditions that are causally related toaberrant melanogenesis activity, comprising (but not limited to)aberrant pigmentation, including hyperpigmentation of all etiologies,uneven pigmentation, and the like, using the compounds and compositionsdisclosed herein.

Accordingly, a plurality of compounds has been identified that arecapable of controlling, and particularly, inhibiting melanogenesis.These compounds, which were not previously identified as possessing sucha capability, are listed herein and referred to as novel melanogenesismodifiers. Accordingly, the compounds and compositions disclosed hereinare directed to their use in modifying pigmentation in in vitro and invivo applications. With respect to in vitro applications, test-tubebased and additional cell-based assays may be used to test the abilityof modified versions and/or derivatives of compounds listed herein toalter melanogenesis. In vivo applications are directed to theadministration of at least one of the novel melanogenesis inhibitingcompounds listed herein to a subject in need thereof to reducepigmentation levels for prophylactic, therapeutic and/or cosmeticpurposes.

Thus, in one aspect compounds have been identified that are capable ofeffectively and efficiently inhibiting melanogenesis (referred to hereinas melanogenesis inhibitors) in mammalian cells. The ability of suchcompounds to decrease or inhibit melanogenesis may be used to advantageto decrease the melanin content of melanocytes, which, in turn, resultsin decreased pigmentation or lightening of skin, hair, wool, or furcolor. In view of the above, the novel melanogenesis inhibitorsdisclosed herein may be topically applied to skin, hair, wool, or fur tolighten their color.

In one embodiment, benzopyran compounds are disclosed that aremelanogenesis modifiers, such as inhibitors, having a formula (I):

wherein

R³ is selected from H, halo, substituted or unsubstituted alkyl,substituted or unsubstituted alkenyl, or substituted or unsubstitutedaryl; and substituted or unsubstituted heteroaryl;

R⁴ is selected from H, halo, hydroxy, alkoxy, alkenyloxy, substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, andsubstituted or unsubstituted phenyl;

each R⁵, R⁶, and R⁸ is independently selected from H, halo, hydroxy,alkoxy, alkenyloxy, substituted or unsubstituted alkyl, substituted orunsubstituted alkenyl, and substituted or unsubstituted phenyl;

R⁷ is selected from H, halo, hydroxy, alkoxy, alkenyloxy, substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, orheterocycloalkyl; or R⁷ is —P(═O)(alkoxy)₂, or —P(═S)(alkoxy)₂; or

R⁶ and R⁷ or R⁷ and R⁸ are joined to form a 5- or 6-memberedheterocycloalkyl or heterocycloalkenyl; and the heterocycloalkyl orheterocycloalkenyl is unsubstituted or substituted with one more groupsselected from alkyl, alkenyl, hydroxyalkyl, acyloxyalkyl, hydroxy, andalkoxy;

or pharmaceutically acceptable salts, solvates, isomers, tautomers,metabolites, analogs, isotopic variants or prodrugs thereof.

Another aspect of the invention provides a method for preventinginhibiting melanogenesis or a method for promoting skin lighteningcomprising administering an effective amount of a compound of formula I.

Another aspect of the invention provides a method for preventing thehyperpigmentation or undesired darkening of skin comprisingadministering an effective amount of a compound of formula I.

In one embodiment of the invention, with respect to formula I, R⁷ isselected from H, substituted or unsubstituted alkyl, and substituted orunsubstituted alkenyl.

In one embodiment of the invention, with respect to formula I, R³ is H,Cl, alkyl, or substituted or unsubstituted phenyl.

In another embodiment of the invention, with respect to formula I, R³ isH, Cl, Me, phenyl, 4-hydroxyphenyl, or 4-methoxyphenyl.

In one embodiment of the invention, with respect to formula I, R⁴ is H,Cl, alkyl, or substituted or unsubstituted phenyl.

In another embodiment of the invention, with respect to formula I, R⁴ isH, Cl, Me, phenyl, or 4-methoxyphenyl.

In one embodiment of the invention, with respect to formula I, R⁵ is H,Cl, alkyl, hydroxy, or alkoxy.

In another embodiment of the invention, with respect to formula I, R⁵ isH, Cl, Me, OH, or OMe.

In one embodiment of the invention, with respect to formula I, R⁶ is H,Cl, alkyl, alkenyl, hydroxy, alkoxy, or alkenyloxy.

In another embodiment of the invention, with respect to formula I, R⁶ isH, Cl, OH, OMe, 3-methylbut-2-enyl, or 3-methylbut-2-enyloxy.

In one particular embodiment of the invention, with respect to formulaI, R⁶ is H, H, or OMe.

In one embodiment of the invention, with respect to formula I, R⁸ is H,Cl, alkyl, alkenyl, hydroxy, alkoxy, or alkenyloxy.

In another embodiment of the invention, with respect to formula I, R⁸ isH, Cl, OH, OMe, 3-methylbut-2-enyl, or 3-methylbut-2-enyloxy.

In one particular embodiment of the invention, with respect to formulaI, R⁸ is H, OH, OMe, or 3-methylbut-2-enyl.

In one particular embodiment of the invention, with respect to formulaI, R⁷ is H, Me, 3-methylbut-2-enyl, P(═O)(OEt)₂, P(═S)(OEt)², or6-hydroxymethyl-3,4,5-trihydroxypyran-2-yl.

In one particular embodiment of the invention, with respect to formulaI, each R³, R⁴, R⁵, R⁶ is H; R⁷ is as described for formula I; and R⁸ issubstituted or unsubstituted alkenyl. In another embodiment, R⁸ is3-methylbut-2-enyl.

In one particular embodiment of the invention, with respect to formulaI, each R³, R⁴, R⁵, R⁶ is H; R⁸ is substituted or unsubstituted alkenyl;and R⁷ is H, Me, 3-methylbut-2-enyl, P(═O)(OEt)₂, P(═S)(OEt)₂, or6-hydroxymethyl-3,4,5-trihydroxypyran-2-yl. In another embodiment, R⁸ issubstituted or unsubstituted alkenyl; and R⁷ is Me. In yet anotherparticular embodiment, R⁸ is 3-methylbut-2-enyl and R⁷ is Me.

In one particular embodiment of the invention, with respect to formulaI, R⁴, R⁵, R⁶, R⁷ and R⁸ are as described for formula I; and R³ is

In one particular embodiment of the invention, with respect to formulaI, R⁴, R⁵, R⁶, and R⁸ are as described for formula I; and R³ is Cl; andR⁷ is H, Me, 3-methylbut-2-enyl, P(═O)(OEt)₂, P(═S)(OEt)₂, or6-hydroxymethyl-3,4,5-trihydroxypyran-2-yl.

In another embodiment, with respect to formula I, R⁷ is Me, orP(═S)(OEt)₂. In yet another embodiment, R⁷ is Me, or P(═S)(OEt)₂.

In another embodiment, with respect to formula I, R⁷ is Me.

In one embodiment of the invention, with respect to formula I, R⁶ and R⁷are joined to form a 5- or 6-membered heterocycloalkyl orheterocycloalkenyl; and the heterocycloalkyl or heterocycloalkenyl isunsubstituted or substituted with one more groups selected from alkyl,alkenyl, hydroxyalkyl, acyloxyalkyl, hydroxy, and alkoxy.

In one embodiment of the invention, with respect to formula I, R⁷ and R⁸are joined to form a 5- or 6-membered heterocycloalkyl orheterocycloalkenyl; and the heterocycloalkyl or heterocycloalkenyl isunsubstituted or substituted with one more groups selected from alkyl,alkenyl, hydroxyalkyl, acyloxyalkyl, hydroxy, and alkoxy.

In one embodiment of the invention, with respect to formula I, thecompound is according to formulae IIa, IIb, IIc, or IId:

or a pharmaceutically acceptable salt, solvate or prodrug thereof, andstereoisomers, tautomers and isotopic variants thereof; and wherein

R⁴, R⁵, and R⁶ are as described for formula I;

R³ is selected from halo, substituted or unsubstituted alkyl,substituted or unsubstituted alkenyl, or substituted or unsubstitutedphenyl;

R⁸ is selected from H, halo, hydroxy, alkoxy, alkenyloxy, substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, orsubstituted or unsubstituted phenyl; and

each R^(6a), R^(7a), R^(7b), and R^(8a) is independently selected fromH, alkyl, hydroxyalkyl, or alkenyl.

In one embodiment of the invention, with respect to formula I, thecompound is according to formulae IIIa, IIIb, IIIc or IIId:

or a pharmaceutically acceptable salt, solvate or prodrug thereof, andstereoisomers, tautomers and isotopic variants thereof; and wherein

R⁴, R⁵, and R⁶ are as described for formula I;

R³ is selected from halo, substituted or unsubstituted alkyl,substituted or unsubstituted alkenyl, or substituted or unsubstitutedphenyl;

R⁸ is selected from H, halo, hydroxy, alkoxy, alkenyloxy, substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, orsubstituted or unsubstituted phenyl; and

each R^(6a), R^(7a) and R^(7b) is independently selected from H, alkyl,hydroxyalkyl, or alkenyl.

In one embodiment of the invention, with respect to formulae IIc, IId,IIIc, or IIId, R^(8a) is H or Me.

In one embodiment of the invention, with respect to formulae IIc, IId,IIIc, or IIId, R⁶ is H, Me, OH, OMe, 3-methylbuten-2-yl; or3-methylbuten-2-yloxy.

In one embodiment of the invention, with respect to formula I, thecompound is according to formula IV:

or a pharmaceutically acceptable salt, solvate or prodrug thereof, andstereoisomers, tautomers and isotopic variants thereof; and wherein

R⁴, and R⁵ are as described for formula I;

R³ is selected from halo, substituted or unsubstituted alkyl,substituted or unsubstituted alkenyl, or substituted or unsubstitutedphenyl;

R⁸ is selected from H, halo, hydroxy, alkoxy, alkenyloxy, substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, orsubstituted or unsubstituted phenyl; and

each R^(6a) and R^(7a) is independently selected from H, alkyl, oralkenyl.

In one embodiment of the invention, with respect to formulae I-IV, R⁴ isH, Cl, alkyl, hydroxy, alkoxy, or substituted or unsubstituted phenyl.

In one embodiment of the invention, with respect to formulae I-IV, R⁴ isH, Me, OH, OMe, or 4-methoxyphenyl.

In one embodiment of the invention, with respect to formulae I-IV, R⁴ isH.

In one embodiment of the invention, with respect to formulae IIa-IV,R^(6a) is H or Me.

In one embodiment of the invention, with respect to formulae IIa-IV,R^(6a) is H.

In one embodiment of the invention, with respect to formulae IIa-IV,R^(7a) is H or Me.

In one embodiment of the invention, with respect to formulae IIa-IV,R^(7b) is H or Me.

In one embodiment of the invention, with respect to formulae IIa-IV,each R^(7a) and R^(7b) is H or Me.

In one embodiment of the invention, with respect to formulae IIa-IV,each R^(7a) and R^(7b) is Me.

In one embodiment of the invention, with respect to formulae IIa-IV,R^(8a) is H or Me.

In one embodiment of the invention, with respect to formula I, thecompound is of formula Va, or Vb:

or a pharmaceutically acceptable salt, solvate or prodrug thereof, andstereoisomers, tautomers and isotopic variants thereof;

wherein

R⁴, R⁵, and R⁶ are as in formula I;

R³ is selected from halo, substituted or unsubstituted alkyl,substituted or unsubstituted alkenyl, or substituted or unsubstitutedphenyl; and

R⁸ is selected from H, halo, hydroxy, alkoxy, alkenyloxy, substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, orsubstituted or unsubstituted phenyl.

In one embodiment of the invention, with respect to formulae I-Vb, R⁵ isH, Cl, alkyl, hydroxy, or alkoxy.

In one embodiment of the invention, with respect to formulae I-Vb, R⁵ isH, Cl, Me, OH, or OMe.

In one embodiment of the invention, with respect to formulae I-Vb, R⁵ isOH.

In one embodiment of the invention, with respect to formulae I-Vb, R⁸ isH, Cl, alkyl, alkenyl, hydroxy, alkoxy, or alkenyloxy.

In one embodiment of the invention, with respect to formulae I-Vb, R⁸ isH, Cl, OH, OMe, 3-methylbut-2-enyl, or 3-methylbut-2-enyloxy.

In one embodiment of the invention, with respect to formulae I-Vb, R⁸ is3-methylbut-2-enyl.

In one embodiment of the invention, with respect to formulae I-Vb, R⁶ isH, Cl, alkyl, alkenyl, hydroxy, alkoxy, or alkenyloxy.

In one embodiment of the invention, with respect to formulae I-Vb, R⁶ isH, Cl, OH, OMe, 3-methylbut-2-enyl, or 3-methylbut-2-enyloxy.

In one embodiment of the invention, with respect to formulae I-Vb, R⁶ is3-methylbut-2-enyl.

In one embodiment of the invention, with respect to formula I, thecompound is of formula VIa, or VIb:

or a pharmaceutically acceptable salt, solvate or prodrug thereof, andstereoisomers, tautomers and isotopic variants thereof; and wherein

R³ is selected from halo, substituted or unsubstituted alkyl,substituted or unsubstituted alkenyl, or substituted or unsubstitutedphenyl.

In one embodiment of the invention, with respect to formulae I-VIb, R³is Cl, alkyl, or substituted or unsubstituted phenyl.

In one embodiment of the invention, with respect to formulae I-VIb, R³is Me, phenyl, 4-hydroxyphenyl, 3,4-dihydroxyphenyl, 4-methoxyphenyl, or3,4-dimethoxyphenyl. In one particular embodiment, R³ is4-hydroxyphenyl, or 3,4-dihydroxyphenyl. In a more particularembodiment, R³ is 4-methoxyphenyl, or 3,4-dimethoxyphenyl.

In one embodiment of the invention, with respect to formula I, thecompound is of formula VIIa, VIIb, or VIIc:

or a pharmaceutically acceptable salt, solvate or prodrug thereof, andstereoisomers, tautomers and isotopic variants thereof.

In one embodiment of the invention, with respect to formula I, thecompound is osajin-4′ methylether, or pomiferin-3′,4′-dimethyl ether.

In one embodiment of the invention, with respect to formula I, thecompound is warangalone or warangalone-4′-methylether.

In another particular embodiment, with respect to formula I, thecompound is selected from the compounds listed in Table 1.

In another aspect, the invention provides methods for inhibitingmelanogenesis using the compounds of formulae I-VIIc.

In another aspect, the invention provides methods for inhibitingmelanogenesis using a plant extract containing compounds of formula I.In one embodiment the plant extract is derived from the fruit of Maclurapomifera.

In another aspect, the invention provides methods for promoting skinlightening using the compounds of formulae I-VIIc.

In another aspect, the invention provides methods for promoting skinlightening using a plant extract containing compounds of formula I. Inone embodiment the plant extract is derived from the fruit of Maclurapomifera.

A further aspect extends to a formulation that comprises a combinationof a compound with respect to formulae I-VIIc, and an additionalpharmaceutical or cosmetic agent. In one embodiment, the additionalpharmaceutical or cosmetic agent is a like-acting agent. In a particularembodiment, the like acting agent is selected from a cosmetic ingredientand a pharmacologically active agent.

In one embodiment of the combination just described, a pharmaceuticalcomposition is prepared that is useful to treat a disease for which amelanogenesis inhibitor is indicated, which comprises a therapeuticallyeffective amount of the combination, wherein the like acting agent is apharmacologically active agent. More particularly, the like-acting agentis a skin lightening or skin bleaching compound. In some embodiments,the skin lightening or skin bleaching compound is hydroquinone, kojicacid, ascorbic acid, magnesium ascorbyl phosphate or ascorbylglucosamine, or mixtures thereof.

In a further embodiment of the combination described above, a topicalformulation is prepared that comprises a composition for cosmetic ordermatological use, which composition comprises a cosmetically and/ordermatologically effective amount of the combination stated above,wherein the like acting agent is a cosmetically active agent. Moreparticularly, the like-acting agent is a skin lightening or skinbleaching compound. In some embodiments, the skin lightening or skinbleaching compound is hydroquinone, kojic acid, ascorbic acid, magnesiumascorbyl phosphate or ascorbyl glucosamine, or mixtures thereof.

In another embodiment of the combination described above, the additionalpharmaceutical or cosmetic agent is a skin care active agent. In someembodiments, the skin care active agent is an abrasive, an absorbent, anastringent, an aesthetic component, such as fragrances, pigments,colorings/colorants, essential oils, skin sensates, astringents andother aesthetic components, an antioxidant, a reducing agent, asequestrant, a skin bleaching or lightening agent, a skin conditioningagent, for example humectants and emollients, a skin soothing agent, askin healing agent, such as pathenol and derivatives, aloe vera,pantothenic acid, allantoin, bisbolol, dipotassium glycyrrhizinate, skintreating agents, vitamins and derivatives, such as a retinoid, ormixtures thereof. In some embodiments, the retinoid is retinol, retinal,retinol esters, retinyl propionate, retinoic acid, retinyl palmitate, ormixtures thereof.

In a further aspect, methods are also provided for preventing, treating,ameliorating or managing a disease or condition involving undesired oraberrant melanogenesis, which comprises administering to a patient inneed or desirous of such prevention, treatment, amelioration ormanagement, a pharmaceutical composition comprising a prophylacticallyor therapeutically effective melanogenesis-inhibiting amount of thecombination as stated and set forth above, wherein the like acting agentis a pharmaceutically active agent. More particularly, the like-actingagent is a skin lightening or skin bleaching compound. In someembodiments, the skin lightening or skin bleaching compound ishydroquinone, kojic acid, ascorbic acid, magnesium ascorbyl phosphate orascorbyl glucosamine, or mixtures thereof.

A method for altering or restoring pigmentation in mammalian skin, hair,wool or fur comprising administering to the mammalian skin, hair, woolor fur an amount of a composition comprising a pigment restoring oraltering-effective amount of the combination as stated and set forthabove, wherein the like acting agent is a cosmetically active agent.More particularly, the like-acting agent is a skin lightening or skinbleaching compound. In some embodiments, the skin lightening or skinbleaching compound is hydroquinone, kojic acid, ascorbic acid, magnesiumascorbyl phosphate or ascorbyl glucosamine, or mixtures thereof.

The methods and compositions disclosed herein contemplate the use of oneor more of the compounds listed herein as an active ingredient(s) forvarious uses. In a particular embodiment, the active ingredient(s) iscombined with an acceptable carrier to form a topical formulation forapplication to the skin, for example, for cosmetic and/or therapeuticdermatological uses. Topical formulations may include ointments,lotions, pastes, creams, gels, drops, suppositories, sprays, liquids,shampoos, powders, antiperspirants, deodorants, rinses, soaps, topicalmake-up products, including but not limited to face power, foundation,rouge, eye shadow, mascara, eyeliner or lipstick, UV-protectiveproducts, which may include sunscreens, lotions or creams, andtransdermal patches. Thickeners, diluents, emulsifiers, dispersing aidsor binders may be used as needed. Preferably, one function of thecarrier is to enhance skin penetration of the active ingredient(s), andshould be capable of delivering the active ingredient(s) to melanocytesunder in vivo conditions. Suitable carriers are well known to skilledpractitioners, and include liposomes, ethanol, dimethylsulfoxide (DMSO),petroleum jelly (petrolatum), mineral oil (liquid petrolatum), water,dimethylformamide, dekaoxyethylene-oleylether, oleic acid, 2-pyrrolidoneand Azone® brand penetration enhancer (Upjohn). A particular compositionmay be formulated to include an active ingredient(s) as described inTable 1, with one of 2-pyrrolidone, oleic acid and/or Azone® added toenhance penetration, solubilized in a base of water, ethanol, propanoland/or propylene glycol.

As indicated above, vehicles comprising liposomes may be used fortopical delivery of some of the compositions disclosed herein. Dependingon the composition, and at the discretion of a skilled practitioner,such liposomes may be non-ionic and contain a) glycerol dilaurate(preferably in an amount of between about 5% and about 70% by weight);b) compounds having the benzopyran core found in cholesterol (preferablyin an amount of between about 5% and about 45% by weight); and c) one ormore fatty acid ethers having from about 12 to about 18 carbon atomspreferably in an amount of between about 5% and about 70% by weightcollectively), wherein the constituent compounds of the liposomes arepreferably in a ratio of about 37.5:12.5:33.3:16.7. For somecompositions, liposomes comprised of glyceroldilaurate/cholesterol/polyoxyethylene-10-stearylether/polyoxyethylene-9-lauryl ether (GDL liposomes) are preferred.Liposomes may be present in an amount, based upon the total volume ofthe composition, of from about 10 mg/mL to about 100 mg/mL, and morepreferably from about 20 mg/mL to about 50 mg/mL. A ratio of about37.5:12.5:33.3:16.7 may be used to particular advantage. Suitableliposomes may be prepared in accordance with standard methods commonlyused in the art.

The above described composition may be prepared by combining the desiredcomponents in a suitable container and mixing them under ambientconditions in any conventional high shear mixing means well known in theart for non-ionic liposome preparations, such as those disclosed inNiemiec et al. (Pharm. Res. 12:1184-88 (1995)), which is incorporated byreference herein in its entirety. The presence of such liposomesenhances the depigmenting capabilities of some compositions.

Other formulations may contain, for example, soybean milk or otherliquid formulations derived directly from legumes or other suitableplant. Such a formulation may, for example, contain a large proportionof soybean milk, an emulsifier that maintains the physical stability ofthe soybean milk, and, optionally a chelating agent, preservatives,emollients, humectants and/or thickeners or gelling agents.

Oil-in-water emulsions, water-in-oil emulsions, solvent-basedformulations and aqueous gels known to those of skill in the art mayalso be utilized as vehicles for the delivery of the disclosedcompositions.

Depending on the specific application, the compositions disclosed hereinmay also include other active ingredients, as well as inert or inactiveingredients. In such alternative embodiments, the topically activepharmaceutical or cosmetic composition may be optionally combined withother ingredients such as moisturizers, cosmetic adjuvants, surfactants,foaming agents, conditioners, humectants, fragrances, viscosifiers,buffering agents, preservatives, sunscreens and the like.

Particular formulations may include at least one active ingredient (forexample, a novel melanogenesis modifier described herein) or previouslyrecognized, and particularly, like-acting agents, such as skinlighteners or skin bleachers, which may be known to those of skill inthe art. Agents known to possess similar activities and/or propertiesinclude, but are not limited to: bleaching agents; tyrosinaseinhibitors; α-hydroxy acids, salts and derivatives thereof; α-ketoacids, salts and derivatives thereof; β-hydroxy acids, salts andderivatives thereof; retinoids, salts and derivatives thereof; Vitamin Aand related compounds; acids; phenol; methoxypropyl-gluconamide;corticosteroids; agents that block the transfer of melanosomes tokeratinocytes, such as may be found in soy extracts; kojic acid;licorice extracts; and the like. In some embodiments, the retinoidsinclude retinol, retinal, retinol esters, retinyl propionate, retinoicacid, retinyl palmitate or mixtures thereof.

The dose regimen will depend on a number of factors which may readily bedetermined, such as severity and responsiveness of the condition to betreated, but will normally be one or more doses per day, with a courseof treatment lasting from several days to several months, or until acure is effected or a diminution of disease state is achieved, or acosmetically desired degree of melanogenesis modification (e.g.,reduction in pigmentation) is achieved, depending on the application.One of ordinary skill may readily determine optimum dosages, dosingmethodologies and repetition rates. In general, it is contemplated thatthe compositions disclosed herein will have a concentration of amelanogenesis inhibitor of from about 0.01% to about 50%, preferablyfrom about 0.03% to about 10%. In some embodiments, the compositionsdisclosed herein will have a concentration of melanogenesis inhibitor offrom about 0.1% to about 25%, or from about 1% to about 10%. In otherembodiments, the compositions disclosed herein will have a concentrationof from about 0.1% to about 75%, from about 0.5% to about 60%, fromabout 0.5% to about 50%, from about 0.5% to about 40%, from about 0.5%to about 30%, from about 0.5% to about 20%, from about 0.5% to about10%, from about 1% to about 75%, from about 1% to about 60%, from about1% to about 50%, from about 1% to about 40%, from about 1% to about 30%,from about 1% to about 20%, from about 1% to about 10%, from about 5% toabout 75%, from about 5% to about 60%, from about 5% to about 50%, fromabout 5% to about 40%, from about 5% to about 30%, from about 5% toabout 20%, from about 5% to about 10%, from about 10% to about 75%, fromabout 10% to about 60%, from about 10% to about 50%, from about 10% toabout 40%, from about 10% to about 30%, from about 10% to about 20%, andfrom about 10% to about 15%. In some embodiments, the compositionsdisclosed herein will have a concentration of melanogenesis inhibitor of0.1%, 0.5%, 0.75%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%,5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5%, 9.0%, 9.5%, 10%, 10.5%, 11%,11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, 16%, 17%, 18%, 19%, 20%,25%, 30%, 35% 40%, 45% or 50%.

It is also contemplated that the compositions disclosed herein maycontain from about 0.01 mg to about 100 mg of melanogenesis inhibitor,preferably about 0.1 mg to about 10 mg of melanogenesis inhibitor. Insome embodiments, the compositions disclosed herein may Contain fromabout 0.05 to about 5 mg of melanogenesis inhibitor, or from about 0.1to about 3 mg of melanogenesis inhibitor. In some embodiments, thecompositions disclosed herein may contain from about 0.1 to about 50 mg,from about 0.1 to about 45 mg, from about 0.1 to about 40 mg, from about0.1 to about 35 mg, from about 0.1 to about 30 mg, from about 0.1 toabout 25 mg, from about 0.1 to about 20 mg, from about 0.1 to about 15mg, from about 0.1 to about 10 mg, from about 0.1 to about 5 mg, fromabout 0.5 to about 50 mg, from about 0.5 to about 45 mg, from about 0.5to about 40 mg, from about 0.5 to about 35 mg, from about 0.5 to about30 mg, from about 0.5 to about 25 mg, from about 0.5 to about 20 mg,from about 0.5 to about 15 mg, from about 0.5 to about 10 mg, from about0.5 to about 5 mg, from about 1.0 to about 50 mg, from about 1.0 toabout 45 mg, from about 1.0 to about 40 mg, from about 1.0 to about 35mg, from about 1.0 to about 30 mg, from about 1.0 to about 25 mg, fromabout 1.0 to about 20 mg, from about 1.0 to about 15 mg, from about 1.0to about 10 mg, from about 1.0 to about 5 mg, from about 2.5 to about 50mg, from about 2.5 to about 45 mg, from about 2.5 to about 40 mg, fromabout 2.5 to about 35 mg, from about 2.5 to about 30 mg, from about 2.5to about 25 mg, from about 2.5 to about 20 mg, from about 2.5 to about15 mg, from about 2.5 to about 10 mg, and from about 2.5 to about 5 mg.In some embodiments, the compositions disclosed herein will contain fromabout 0.1 mg, 0.2 mg, 0.3 mg, 0.4 mg, 0.5, mg, 0.6 mg, 0.7 mg, 0.8 mg,0.9 mg, 1.0 mg, 2.0 mg, 3.0 mg, 4.0 mg, 5.0 mg, 7.0 mg, 10.0 mg, 15.0mg, 20 mg, 25 mg, 30 mg, 35 mg, 40 mg, 45 mg, 50 mg, 60 mg, 70 mg, 80mg, 90 mg or 100 mg of melanogenesis inhibitor. In some embodiments, thecompositions disclosed herein will contain from about 0.3 mg to about0.75 mg of melanogenesis inhibitor.

It is further contemplated that the compositions disclosed herein willhave a concentration of melanogenesis inhibitor of from about 0.01 mg/mlto about 50 mg/ml, preferably from about 0.1 mg/ml to about 10 mg/ml. Insome embodiments, the compositions disclosed herein will have aconcentration of melanogenesis inhibitor of from about 0.1 mg/ml toabout 5 mg/ml, or from about 0.3 mg/ml to about 3 mg/ml. In someembodiments, the compositions will have a concentration of melanogenesisinhibitor of from about 0.1 to about 50 mg/ml, from about 0.1 to about45 mg/ml, from about 0.1 to about 40 mg/ml, from about 0.1 to about 35mg/ml, from about 0.1 to about 30 mg/ml, from about 0.1 to about 25mg/ml, from about 0.1 to about 20 mg/ml, from about 0.1 to about 15mg/ml, from about 0.1 to about 10 mg/ml, from about 0.1 to about 5mg/ml, 0.5 to about 50 mg/ml, from about 0.5 to about 45 mg/ml, fromabout 0.5 to about 40 mg/ml, from about 0.5 to about 35 mg/ml, fromabout 0.5 to about 30 mg/ml, from about 0.5 to about 25 mg/ml, fromabout 0.5 to about 20 mg/ml, from about 0.5 to about 15 mg/ml, fromabout 0.5 to about 10 mg/ml, from about 0.5 to about 5 mg/ml, 1.0 toabout 50 mg/ml, from about 1.0 to about 45 mg/ml, from about 1.0 toabout 40 mg/ml, from about 1.0 to about 35 mg/ml, from about 1.0 toabout 30 mg/ml, from about 1.0 to about 25 mg/ml, from about 1.0 toabout 20 mg/ml, from about 1.0 to about 15 mg/ml, from about 1.0 toabout 10 mg/ml, from about 1.0 to about 5 mg/ml, 2.5 to about 50 mg/ml,from about 2.5 to about 45 mg/ml, from about 2.5 to about 40 mg/ml, fromabout 2.5 to about 35 mg/ml, from about 2.5 to about 30 mg/ml, fromabout 2.5 to about 25 mg/ml, from about 2.5 to about 20 mg/ml, fromabout 2.5 to about 15 mg/ml, from about 2.5 to about 10 mg/ml, fromabout 2.5 to about 5 mg/ml. In some embodiments, the compositionsdisclosed herein will have a concentration of melanogenesis inhibitor of0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, 2.0, 2.5, 3.0,3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10,10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 16, 17, 18, 19, 20,25, 30, 35, 40, 45 or 50 mg/ml.

In general, melanogenesis inhibitors or compounds that decrease orsuppress melanin production and pigmentation in mammalian skin, hair,fur or wool are useful in, for example, the lightening and/orbrightening of skin, hair, wool or fur for cosmetic purposes, or thetreatment of hyperpigmentation or uneven pigmentation disorders such asvitiligo, ephelides, lentigines, dermal melanocytosis, cafe-au-laitspots, post-inflammatory hyperpigmentation, etc. For such depigmentationapplications, the formulation and dosing would be as described above.

In certain aspects, prodrugs and derivatives of the disclosed compoundsare provided. Prodrugs are derivatives of the compounds which havemetabolically cleavable groups and become by solvolysis or underphysiological conditions the compounds which are pharmaceuticallyactive, in vivo. Such examples include, but are not limited to, cholineester derivatives and the like, N-alkylmorpholine esters and the like.

Other derivatives of the compounds have activity in both their acid andacid derivative forms, but the acid sensitive form often offersadvantages of solubility, tissue compatibility, or delayed release inthe mammalian organism (see, Bundgard, H., Design of Prodrugs, pp. 7-9,21-24, Elsevier, Amsterdam 1985). Prodrugs include acid derivatives wellknow to practitioners of the art, such as, for example, esters preparedby reaction of the parent acid with a suitable alcohol, or amidesprepared by reaction of the parent acid compound with a substituted orunsubstituted amine, or acid anhydrides, or mixed anhydrides. Simplealiphatic or aromatic esters, amides and anhydrides derived from acidicgroups pendant on the disclosed compounds are preferred prodrugs. Insome cases it is desirable to prepare double ester type prodrugs such as(acyloxy)alkyl esters or ((alkoxycarbonyl)oxy)alkylesters. Preferred arethe substituted or unsubstituted C₁ to C₈ alkyl, substituted orunsubstituted C₂-C₈ alkenyl, aryl, substituted or unsubstituted C₇-C₁₂aryl, and substituted or unsubstituted C₇-C₁₂ arylalkyl esters of thecompounds.

Also included are pharmaceutically acceptable acid addition and basesalts of any of the aforementioned compounds of formulae I-VIIc. Theacids which are used to prepare the pharmaceutically acceptable acidaddition salts of the aforementioned base compounds are those which formnon-toxic acid addition salts, i.e., salts containing pharmacologicallyacceptable anions, such as the hydrochloride, hydrobromide, hydroiodide,nitrate, sulfate, bisulfate, phosphate, acid phosphate, acetate,lactate, citrate, acid citrate, tartrate, bitartrate, succinate,maleate, fumarate, gluconate, saccharate, benzoate, methanesulfonate,ethanesulfonate, benzenesulfonate, p-toluenesulfonate and pamoate (i.e.,1,1-methylene-bis-(2-hydroxy-3-naphthoate)) salts.

The compounds useful that are basic in nature are capable of forming awide variety of different salts with various inorganic and organicacids. Although such salts must be pharmaceutically acceptable foradministration to animals, it is often desirable in practice toinitially isolate a compound of formula I from the reaction mixture as apharmaceutically unacceptable salt and then simply convert the latterback to the free base compound by treatment with an alkaline reagent andsubsequently convert the latter free base to a pharmaceuticallyacceptable acid addition salt. The acid addition salts of the activebase compounds disclosed herein are readily prepared by treating thebase compound with a substantially equivalent amount of the chosenmineral or organic acid in an aqueous solvent medium or in a suitableorganic solvent, such as methanol or ethanol. Upon careful evaporationof the solvent, the desired solid salt is readily obtained.

Those compounds useful that are acidic in nature are capable of formingbase salts with various pharmaceutically acceptable cations. Examples ofsuch salts include the alkali metal and alkaline earth metal salts and,particularly, the sodium and potassium salts. These salts can beprepared by conventional techniques. The chemical bases that are used asreagents to prepare the pharmaceutically acceptable base salts of thecompounds disclosed herein are those that form non-toxic base salts withthe acidic compounds of formulae I-VIIc. Such non-toxic base saltsinclude those derived from such pharmaceutically acceptable cations assodium, potassium, calcium and magnesium, etc. These salts can easily beprepared by treating the corresponding acidic compounds with an aqueoussolution containing the desired pharmaceutically acceptable cations, andthen evaporating the resulting solution to dryness, preferably underreduced pressure. Alternatively, they can also be prepared by mixinglower alkanolic solutions of the acidic compounds and the desired alkalimetal alkoxide together, and then evaporating the resulting solution todryness, as described above. In either case, stoichiometric quantitiesof reagents are preferably employed in order to ensure completeness ofreaction and maximum yields of the desired final products.

The compounds and their pharmaceutically acceptable salts are useful inthe treatment of disorders of human pigmentation, including solar andsimple lentigines (including age/liver spots), melasma/chloasma and postinflammatory hyper-pigmentation. Such compounds reduce skin melaninlevels by inhibiting the production of melanin, whether the latter isproduced constitutively or in response to UV irradiation (such as sunexposure). Thus, some of the active compounds used can be used to reduceskin melanin content in non-pathological states so as to induce alighter skin tone, as desired by the user, or to prevent melaninaccumulation in skin that has been exposed to UV irradiation. They canalso be used in combination with skin peeling agents (including glycolicacid or trichloroacetic acid face peels) to lighten skin tone andprevent repigmentation.

The appropriate dose regimen, the amount of each dose administered, andspecific intervals between doses of the active compound will depend uponthe particular active compound employed, the condition of the patientbeing treated, and the nature and severity of the disorder or conditionbeing treated. Preferably, the melanogenesis inhibitor is administeredin an amount and at an interval that results in the desired treatment ofor improvement in the disorder or condition being treated.

For skin lightening, a melanogenesis inhibitor disclosed herein can alsobe used in combination with sun screens (UVA or UVB blockers) to preventrepigmentation, to protect against sun or UV-induced skin darkening orto enhance their ability to reduce skin melanin and their skin bleachingaction. For skin lightening, a melanogenesis inhibitor can also be usedin combination with retinoic acid or its derivatives or any compoundsthat interact with retinoic acid receptors and accelerate or enhance theability to reduce skin melanin and skin bleaching action, or enhance theability to prevent the accumulation of skin melanin. For skinlightening, a melanogenesis inhibitor can also be used in combinationwith 4-hydroxyanisole. For skin lightening, the melanogenesis inhibitorcan also be used in combination with ascorbic acid, its derivatives andascorbic-acid based products (such as magnesium ascorbate) or otherproducts with an anti-oxidant mechanism (such as resveratrol or vitaminA or retinoic acid) which accelerate or enhance their ability to reduceskin melanin and their skin bleaching action.

Also provided are compounds useful to decrease melanin production or toreduce skin pigmentation, which correspond to compounds of the formulaeI-VIII, and prodrugs, and analogs thereof, and to pharmaceuticalcompositions containing them, and including any pharmaceuticallyacceptable salts or solvates thereof.

Although methods and materials similar or equivalent to those describedherein can be used in the practice or testing of the compositions andcompounds disclosed herein, preferred methods and materials aredescribed below. The materials, methods, and examples are illustrativeonly and not intended to be limiting. Other features and advantages willbe apparent from the detailed description, examples, and the claims.

Plant Extract Containing Benzopyrans of Formula I

In some embodiments are methods of inhibiting melanogenesis comprisingadministering to melanocytes an effective amount of a plant extractcontaining a melanogenesis inhibitor. In some embodiments, themelanogenesis inhibitor is a benzopyran melanogenesis inhibitor as inFormula I. In some embodiments, the melanogenesis inhibitor is an osajinderivative, such as osajin-4′-methyl ether. In further embodiments, themelanogenesis inhibitor is pomiferin-3′,4′-dimethyl ether or apomiferin-3′,4′-dimethyl ether derivative. In some embodiments, theplant extract is derived from a plant of the Osage family. In someembodiments, the plant extract is derived from the fruit of Maclurapomifera or its extract. The plant species listed are not meant to belimiting as to the source of the melanogenesis inhibitor. Other plantspecies from which plant extracts can be prepared comprising amelanogenesis inhibitor, including an osajin derivative, such asosajin-4′-methyl ether or pomiferin-3′,4′-dimethyl ether or apomiferin-3′,4′-dimethyl ether derivative, may also be used inconjunction with the disclosure herein.

In some embodiments, the plant extract is substantially purified orpartially purified for concentration of the melanogenesis inhibitor. Inyet other embodiments, the plant extract may be substantially liquefiedor partially liquefied for administration to a patient in need thereof.The plant extract may also be processed to remove particulate matterprior to administration. In some embodiments, the plant extract containsabout 0.1 to about 90%, about 0.5% to about 80%, about 1% to about 75%,about 5% to about 60%, about 10% to about 50%, about 25% to about 40%melanogenesis inhibitor. In other embodiments, the plant extractcontains about 1% to about 80%, about 1% to about 70%, about 1% to about60%, about 1% to about 50%, about 1% to about 40%, about 1% to about30%, about 1% to about 20%, about 1% to about 10%, about 5% to about80%, about 5% to about 70%, about 5% to about 60%, about 5% to about50%, about 5% to about 40%, about 5% to about 30%, about 5% to about20%, about 5% to about 10%, about 10% to about 80%, about 10% to about70%, about 10% to about 60%, about 10% to about 50%, about 10% to about40%, about 10% to about 30% or about 10% to about 20% melanogenesisinhibitor. In some embodiments, the plant extract contains about 0.5%,1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%,75%, 80%, 85%, 90%, or 95% of a melanogenesis inhibitor.

In some embodiments, a plant extract is provided containing an osajinderivative, such as osajin-4′-methyl ether for use as an inhibitor ofmelanogenesis. In some embodiments, a plant extract is providedcontaining pomiferin-3′,4′-dimethyl ether or a pomiferin-3′,4′-dimethylether derivative. In some embodiments, provided are formulations of aplant extract containing an osajin derivative, such as osajin-4′-methylether for inhibiting melanogenesis. In some embodiments, provided areformulations of a plant extract containing pomiferin-3′,4′-dimethylether or a pomiferin-3′,4′-dimethyl ether derivative. Also provided aremethods for preventing, treating, ameliorating or managing a disease orcondition involving undesired or aberrant melanogenesis, which comprisesadministering to a patient in need thereof or desirous of suchprevention, treatment, amelioration, or management, a prophylactically,therapeutically or cosmetically effective melanogenesis-inhibitingamount of a plant extract containing an osajin derivative, such asosajin-4′-methyl ether, or pomiferin-3′,4′-dimethyl ether or apomiferin-3′,4′-dimethyl ether derivative. In some embodiments, providedare methods for altering or restoring pigmentation in mammalian skin,hair, wool, or fur comprising administering to a mammalian skin, hair,wool or fur an effective amount of a plant extract containing an osajinderivative, such as osajin-4′-methyl ether or pomiferin-3′,4′-dimethylether, or a pomiferin-3′,4′-dimethyl ether derivative. One example ofsuch plant extract is extract derived from the fruit of Maclurapomifera.

Maclura pomifera fruit extract can be prepared from Maclura pomiferafruit powder. In a representative preparation of, the plant extract, 5grams of Maclura pomifera fruit powder is suspended in 25 ml of 200proof ethanol, and incubated overnight at room temperature on anagitator. The mixture is then centrifuged twice at 1000 rpm for 10 minin a swing rotor, and then an additional 5 min as above. The supernatantis then filtered through Whatman Grade 1 (11 micron) filter paper. Theclarified fluid is then further allowed to settle for an hour, and thesupernatant is removed and used as the ethanolic extract of the fruit ofMaclura pomifera.

Extract derived from the fruit of Maclura pomifera may contain a potentinhibitor of melanin synthesis in cultured melanocytes and may be aneffective depigmenting agent in human skin tissues. In general, it iscontemplated that the plant extract compositions disclosed herein willcomprise plant extract of from about 1% to about 75%, preferably fromabout 5% to about 50%, more preferably from about 10% to about 30%, andmore preferably about 20%. In some embodiments, the compositionsdisclosed herein will have an amount of plant extract of from about 5%to about 35%, or from about 15% to about 25%. In some embodiments, thecompositions disclosed herein will have an amount of plant extract offrom about 5% to about 75%, from about 5% to about 70%, from about 5% toabout 65%, from about 5% to about 60%, from about 5% to about 55%, fromabout 5% to about 50%, from about 5% to about 45%, from about 5% toabout 40%, from about 5% to about 35%, from about 5% to about 30%, fromabout 5% to about 25%, from about 5% to about 20%, from about 5% toabout 15%, from about 5% to about 10%, from about 10% to about 75%, fromabout 10% to about 70%, from about 10% to about 65%, from about 10% toabout 60%, from about 10% to about 55%, from about 10% to about 50%,from about 10% to about 45%, from about 10% to about 40%, from about 10%to about 35%, from about 10% to about 30%, from about 10% to about 25%,from about 10% to about 20%, and from about 10% to about 15%. In someembodiments, the compositions disclosed herein will have an amount ofplant extract of 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%,14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%,28%, 29%, 30%, 32%, 34%, 35%, 36%, 38%, 40%, 45%, 50%, 55%, 60%, 65%,70% or 75%. The amount of plant extract included in the disclosedcompositions will depend on a number of factors, including the amount ofmelanogenesis inhibitor, including an osajin derivative, such asosajin-4′-methyl ether, or pomiferin-3′,4′-dimethyl ether or apomiferin-3′,4′-dimethyl ether derivative, contained in the plantextract preparation. Testing of the plant extract preparations todetermine the amount of melanogenesis inhibitor included in eachpreparation is contemplated within the scope of the embodimentsdescribed herein.

It is also contemplated that the compositions disclosed herein maycontain from about 10 mg to about 100 g of plant extract per 100 ml ofcomposition, preferably about 1 g to about 50 g of plant extract per 100ml of composition. In some embodiments, the compositions disclosedherein may contain from about 100 mg to about 50 g of plant extract per100 ml of composition, or from about 1 g to about 20 g of plant extractper 100 ml of composition. In some embodiments, the compositionsdisclosed herein may contain from about 100 mg to about 50 g, from about100 mg to about 45 g, from about 100 mg to about 40 g, from about 100 mgto about 35 g, from about 100 mg to about 30 g, from about 100 mg toabout 25 g, from about 100 mg to about 20 g, from about 100 mg to about15 g, from about 100 mg to about 10 g, from about 100 mg to about 5 g,from about 100 mg to about 1 g, 1 g to about 50 g, from about 1 g toabout 45 g, from about 1 g to about 40 g, from about 1 g to about 35 g,from about 1 g to about 30 g, from about 1 g to about 25 g, from about 1g to about 20 g, from about 1 g to about 15 g, from about 1 g to about10 g, from about 1 g to about 5 g, from about 2.5 g to about 50 g, fromabout 2.5 g to about 45 g, from about 2.5 g to about 40 g, from about2.5 g to about 35 g, from about 2.5 g to about 30 g, from about 2.5 g toabout 25 g, from about 2.5 g to about 20 g, from about 2.5 g to about 15g, from about 2.5 g to about 10 g, and from about 2.5 g to about 5 g ofplant extract per 100 ml of composition. In some embodiments, thecompositions disclosed herein will contain from about 0.5 g, 1 g, 2 g, 3g, 4 g, 5 g, 6 g, 7 g, 8 g, 9 g, 10 g, 11 g, 12 g, 13 g, 14 g, 15 g, 16g, 17 g, 18 g, 19 g, 20 g, 21 g, 22 g, 23 g, 24 g, 25 g, 26 g, 27 g, 28g, 29 g, 30 g, 32 g, 35 g, 37 g, 40 g, 45 g, 50 g, 55 g, 60 g, 65 g, 70g or 75 g of plant extract per 100 ml of composition.

In other embodiments, provided are combinations of a plant extractcontaining an osajin derivative, such as osajin-4′-methyl ether, orpomiferin-3′,4′-dimethyl ether or a pomiferin-3′,4′-dimethyl etherderivative and a like-acting agent. One example of such plant extract isextract derived from the fruit of Maclura pomifera. The like-actingagent can be any cosmetic ingredient or a pharmacologically active agentdisclosed herein. Also provided are pharmaceutical compositions usefulin treating disease for which a melanogenesis inhibitor is indicated,comprising a therapeutically effective amount of a plant extractcontaining an osajin derivative, such as osajin-4′-methyl ether, orpomiferin-3′,4′-dimethyl ether or a pomiferin-3′,4′-dimethyl etherderivative in combination with a like-acting agent. In some embodiments,the pharmaceutical composition comprising a plant extract containing anosajin derivative, such as osajin-4′-methyl ether, orpomiferin-3′,4′-dimethyl ether or a pomiferin-3′,4′-dimethyl etherderivative in combination with a like-acting agent is a topicalformulation for cosmetic or dermatological use. In still otherembodiments, methods are provided for preventing, treating, amelioratingor managing a disease or condition involving undesired or aberrantmelanogenesis, which comprises administering to a patient in needthereof or desirous of such prevention, treatment, amelioration ormanagement, a pharmaceutical or cosmetic composition comprisingprophylactically, therapeutically or cosmetically effectivemelanogenesis-inhibiting amount of a combination of a plant extractcontaining an osajin derivative, such as osajin-4′-methyl ether, orpomiferin-3′,4′-dimethyl ether or a pomiferin-3′,4′-dimethyl etherderivative with a like-acting agent. In still other embodiments, alsoprovided are methods for altering or restoring pigmentation in mammalianskin, hair, wool or fur comprising administering to a mammalian skin,hair, wool or fur an amount of a composition comprising apigment-restoring or altering-effective amount of a combination of aplant extract containing an osajin derivative, such as osajin-4′-methylether, or pomiferin-3′,4′-dimethyl ether or a pomiferin-3′,4′-dimethylether derivative with a like-acting agent. In some embodiments, thelike-acting agent is a skin lightening compound.

Methods of Inhibiting Melanogenesis

As stated above, the compounds disclosed herein can be used to treatanimals or, preferably, humans that have diseases, conditions, ordisorders caused by the production or overproduction of melanin. Suchdiseases, conditions, or disorders include those that can becharacterized by discolorations of the skin or hair such as, forexample, hyperpigmentation caused by inflammation or from diseases suchas melasma, or brown spots such as “cafe au lait” macules.Alternatively, a subject may wish to lighten the color of his or herhair or skin.

The terms “treatment”, “therapeutic use”, “cosmetic use” and “medicinaluse” shall refer to any and all uses of the disclosed compositions whichremedy a disease state, one or more symptoms or one or more effects, orotherwise prevent, hinder, retard, or reverse the progression of diseaseor one or more other undesirable symptoms or effects in any waywhatsoever.

The term “about” is used herein to mean approximately, roughly, around,or in the region of. When the term “about” is used in conjunction with anumerical range, it modifies that range by extending the boundariesabove and below the numerical values set forth.

By the phrase “decrease in melanin production” or “inhibitingmelanogenesis” is meant a detectable lowering of the amount of melaninsynthesized de novo by a melanocyte exposed to a compound disclosedherein, as compared with the amount of melanin synthesized de novo by acontrol, untreated melanocyte. The term “lowering” as presently usedrefers, in a first instance, to a decrease of at least about 10%, in afurther instance, to a decrease of at least about 25%, and in a stillfurther instance, to a decrease of at least about 50%, in the amount ofmelanin synthesized de novo.

As one skilled in the art would know in view of this disclosure, thecompounds used in the methods disclosed herein may be used alone or incombination with each other. Moreover, the methods also include theadditional use of other compounds known in the art to affect melaninsynthesis such as tyrosinase inhibitors. Such inhibitors are known tothose skilled in the art and include various derivatives of resorcinol,hydroquinone, kojic acid, melamine, and various types of plant extracts,among others.

Thus, the disclosure relates both to methods of modifying, andparticularly inhibiting the pigmentation of skin in which the activecompound used, or a pharmaceutically acceptable salt thereof, and one ormore of the other active ingredients referred to above are administeredtogether, as part of the same pharmaceutical composition, as well asmethods in which they are administered separately as part of anappropriate dose regimen designed to obtain the benefits of thecombination therapy. The appropriate dose regimen, the amount of eachdose administered, and specific intervals between doses of each activeagent will depend upon the specific combination of active agentsemployed, the condition of the patient being treated, and the nature andseverity of the disorder or condition being treated. Such additionalactive ingredients will generally be administered in amounts less thanor equal to those for which they are effective as single topicaltherapeutic agents. The FDA approved dosages for such active agents thathave received FDA approval for administration to humans are publiclyavailable.

For example, any of the compounds used according to a skin-lighteningmethod disclosed herein may be used in combination with a tyrosinaseinhibitor or other skin-whitening agent as currently known in the art orto be developed in the future, including any one or more of those agentsdescribed in the following patent publications: U.S. Pat. No. 4,278,656to Nagai et al, issued Jul. 14, 1981; U.S. Pat. No. 4,369,174 to Nagaiet al., issued Jan. 18, 1983; U.S. Pat. No. 4,959,393 to Torihara etal., issued Sep. 25, 1990; U.S. Pat. No. 5,580,549 to Fukuda et al.,issued Dec. 3, 1996; U.S. Pat. No. 6,123,959 to Jones et al., issuedSep. 26, 2000; U.S. Pat. No. 6,132,740 to Hu, issued Oct. 17, 2000; U.S.Pat. No. 6,159,482 to Tuloup et al., issued Dec. 12, 2000; WO 99/32077by L'Oreal, published Jul. 1, 1999; WO 99/64025 by Fytokem Prod. Inc.,published Dec. 16, 1999; WO 00/56702 by Pfizer Inc., published Sep. 28,2000; WO 00/76473 by Shiseido Co. Ltd., published Dec. 12, 2000; EP997140 by L'Oreal SA, published May 3, 2000; JP 5221846 by KunimasaTomoji, published Aug. 31, 1993; JP 7242687 by Shiseido Co. Ltd.,published Sep. 19, 1995; JP 7324023 by Itogawa H, published Dec. 12,1995; JP 8012552 by Shiseido Co. Ltd., published Jan. 16, 1996; JP8012554 by Shiseido Co. Ltd., published Jan. 16, 1996; JP 8012557 byShiseido Co. Ltd., published Jan. 16, 1996; JP 8012560 by Shiseido Co.Ltd., published Jan. 16, 1996; JP 8012561 by Shiseido Co. Ltd.,published Jan. 16, 1996; JP 8134090 by Fujisawa, published May 28, 1996;JP 8168378 by Kirinjo KK, published Jul. 2, 1996; JP 8277225 by KansaiKoso KK, published Oct. 22, 1996; JP 9002967 by Sanki Shoji KK,published Jan. 7, 1997; JP 9295927 by Yagi Akira, published Nov. 18,1997; JP 10072330 by Kansai Kouso, published Mar. 17, 1998; JP 10081626by Kamiyama KK, published Mar. 31, 1998; JP 10101543 by Kansai Kouso KK,published Apr. 21, 1998; JP 11071231 by Maruzen Pharm., published Mar.16, 1999; JP 11079934 by Kyodo Nyugyo, published Mar. 23, 1999; JP11246347 by Shiseido Co. Ltd., published Sep. 14, 1999; JP 11246344 byShiseido Co. Ltd., published Sep. 14, 1999; JP 2000-080023 by KaneboLtd., published Mar. 21, 2000; JP 2000-095663 by Kose KK, published Apr.4, 2000; JP 2000-159681 by Hai Tai Confectionary Co. Ltd., publishedJun. 13, 2000; JP 2000-247907 by Kanebo Ltd., published Sep. 12, 2000;JP-9002967 by Sanki Shoji KK, published Jan. 7, 1997; JP-7206753 byNikken Food KK, published Aug. 8, 1995; JP-5320025 by Kunimasa T,published Dec. 3, 1993; and JP-59157009 by Yakurigaku Chuou KE,published Sep. 6, 1984; among others; which patent publications areincorporated herein by reference.

By the phrase “reducing skin pigmentation” is meant a detectabledecrease in the amount of melanin in the skin, preferably causing alightening of the skin as a result of a lowering of the amount ofmelanin synthesized de novo. The term “lowering” as presently usedrefers, in a first instance, to a decrease of at least about 10%, in afurther instance, to a decrease of at least about 25%, and in a stillfurther instance, to a decrease of at least about 50%, in the amount ofmelanin synthesized de novo. This lowering of melanin synthesized denovo is preferably visually distinguishable to the naked eye, i.e.,would not require the aid of a microscope or other such means to detectits occurrence.

Pharmaceutical Applications

For pharmaceutical uses, it is preferred that the compounds disclosedherein are part of a pharmaceutical composition. Pharmaceuticalcompositions, comprising an effective amount of such a compound in apharmaceutically acceptable carrier, can be administered to a patient,person, or animal having a disease, disorder, or condition which is of atype that produces, or overproduces, melanin.

The amount of compound which will be effective in the treatment of aparticular disease, disorder, or condition will depend on the nature ofthe disease, disorder, or condition, and can be determined by standardclinical techniques. Where possible, it is desirable to determine invitro the cytotoxicity of the compound to the tissue type to be treated,and then in a useful animal model system prior to testing and use inhumans.

The compound can be administered for the reduction or increase ofmelanin synthesis by any means that results in contact of the activeagent with its site of action in the body of a mammal. The compounds canbe administered by any conventional means available for use inconjunction with pharmaceuticals, either as individual therapeuticagents or in a combination of therapeutic agents. Each can beadministered alone, but is preferably administered with a pharmaceuticalcarrier selected on the basis of the chosen route of administration andstandard pharmaceutical practice. The pharmaceutical compositions can beadapted for oral, parenteral, rectal, and preferably topical,administration, and can be in unit dosage form, in a manner well knownto those skilled in the pharmaceutical art. Parenteral administrationincludes but is not limited to, injection subcutaneously, intravenously,intraperitoneally or intramuscularly. However, topical application ispreferred.

Cosmetic Applications

In addition to pharmaceutical uses, the methods disclosed herein areuseful for cosmetic purposes. Cosmetic applications for methodsdisclosed herein include the topical application of compositionscontaining one or more compounds to enhance or otherwise alter thevisual appearance of skin or hair. Occurrences in the skin or hair ofnoticeable but undesired pigmentation as a result of melanin production,overproduction or underproduction can be treated using the methodsdisclosed herein. Thus, and as discussed above, the compounds andcompositions can be used to achieve improvements in skin or hairappearance, as by brightening the same, adding or enhancing luster, andthe like. Suitable formulations for these purposes can be prepared bythose skilled in the art, and such details of preparation are consideredwithin the scope.

The phrases “pharmaceutical applications” and “cosmetic applications”are not meant to imply mutual exclusiveness. In some embodiments, acomposition may be applied to both a “pharmaceutical application” and a“cosmetic application” dependent upon the need and course of actioncalled for.

Endpoints and Dosages

An effective dosage and treatment protocol can be determined byconventional means, starting with a low dose in laboratory animals andthen increasing the dosage while monitoring the effects, andsystematically varying the dosage regimen as well. Animal studies,preferably mammalian studies, are commonly used to determine the maximaltolerable dose, or MTD, of a bioactive agent per kilogram weight. Thoseskilled in the art can extrapolate doses for efficacy and avoidance oftoxicity to other species, including humans.

One of ordinary skill in the art will appreciate that the endpointchosen in a particular case will vary according to the disease,condition, or disorder being treated, the outcome desired by thepatient, subject, or treating physician, and other factors. Where thecomposition is being used for cosmetic purposes, such as to lighten skincolor such as, for example, to reverse hyperpigmentation caused by, forexample, inflammation or diseases such as melasma, or to modify haircolor, any one of a number of endpoints can be chosen.

In such instance, endpoints can be defined subjectively such as, forexample, when the subject is simply “satisfied” with the results of thetreatment. For pharmacological applications, the endpoint can bedetermined by the patient's, or the treating physicians, satisfactionwith the results of the treatment. Alternatively, endpoints can bedefined objectively. For example, the patient's or subject's skin orhair in the treated area can be compared to a color chart. Treatment isterminated when the color of the skin or hair in the treated area issimilar in appearance to a color on the chart. Alternatively, thereflectance of the treated skin or hair can be measured, and treatmentcan be terminated when the treated skin or hair attains a specifiedreflectance. Alternatively, the melanin content of the treated hair orskin can be measured. Treatment can be terminated when the melanincontent of the treated hair or skin reaches a specified value. Melanincontent can be determined in any way known to the art, including byhistological methods, with or without enhancement by stains for melanin.

Methods of Administration

The disclosed compounds can be administered topically, e.g., as patches,ointments, creams, gels, lotions, solutions, foams, masks or transdermaladministration. The compounds can also be administered orally in solidor semi-solid dosage forms, such as hard or soft-gelatin capsules,tablets, or powders, or in liquid dosage forms, such as elixirs, syrups,or suspensions. Additionally, the compounds can also be administeredparenterally, in sterile liquid dosage forms or in suppository form.

Because in vivo use is contemplated, the composition is preferably ofhigh purity and substantially free of potentially harmful contaminants,e.g., at least National Food (NF) grade, generally at least analyticalgrade, and preferably at least pharmaceutical grade. To the extent thata given compound must be synthesized prior to use, such synthesis orsubsequent purification shall preferably result in a product that issubstantially free of any potentially contaminating toxic agents thatmay have been used during the synthesis or purification procedures.

Useful pharmaceutical dosage forms for administration of the presentcompounds are described below.

The pharmaceutical compositions can be applied directly to the skin.Alternatively, they can be delivered by various transdermal drugdelivery systems, such as transdermal patches as known in the art. Forexample, for topical administration, the active ingredient can beformulated in a solution, gel, lotion, ointment, cream, suspension,foam, mask, paste, liniment, powder, tincture, aerosol, patch, or thelike in a pharmaceutically or cosmetically acceptable form by methodswell known in the art. The composition can be any of a variety of formscommon in the pharmaceutical or cosmetic arts for topical application toanimals or humans, including solutions, lotions, sprays, creams,ointments, salves, gels, etc., as described below. Preferred agents arethose that are viscous enough to remain on the treated area, those thatdo not readily evaporate, and/or those that are easily removed byrinsing with water, optionally with the aid of soaps, cleansers and/orshampoos. Actual methods for preparing topical formulations are known orapparent to those skilled in the art, and are described in detail inRemington's Pharmaceutical Sciences, 1990 (supra); and PharmaceuticalDosage Forms and Drug Delivery Systems, 6th ed., Williams & Wilkins(1995).

In order to enhance the percutaneous absorption of the activeingredients, one or more of a number of agents can be added in thetopical formulations including, but not limited to, dimethylsulfoxide,dimethylacetamide, dimethylformamide, surfactants, azone, alcohol,acetone, propylene glycol and polyethylene glycol. In addition, physicalmethods can also be used to enhance transdermal penetration such as,e.g., by iontophoresis or sonophoresis. Alternatively, or in addition,liposomes may be employed.

A topically applied composition contains a pharmaceutically effectiveamount of at least one of the disclosed compounds as described herein,and those ingredients as are necessary for use as a carrier, such as anemulsion, a cream, an ointment, an ophthalmic ointment, an aqueoussolution, a lotion or an aerosol. Non-limiting examples of such carriersare described in more detail below and may be found in InternationalPatent Publication WO 00/62742, published Oct. 26, 2000, U.S. Pat. No.5,691,380 to Mason et al., issued on Nov. 25, 1997 and U.S. Pat. No.5,968,528 to Deckner et al., issued on Oct. 19, 1999, U.S. Pat. No.4,139,619 to Chidsey, III, issued on Feb. 13, 1979 and U.S. Pat. No.4,684,635 to Orentreich et al., issued on Aug. 4, 1987 which areincorporated herein by reference. Suitable pharmaceutical carriers arefurther described in Remington's Pharmaceutical Sciences, 17th ed., MackPublishing Company, Easton, Pa. (1990) a standard reference text in thisfield.

The pharmaceutical compositions may also include optional components.Such optional components should be suitable for application tokeratinous tissue, that is, when incorporated into the composition, theyare suitable for use in contact with human keratinous tissue withoutundue toxicity, incompatibility, instability, allergic response, and thelike within the scope of sound medical judgment. In addition, suchoptional components are useful provided that they do not unacceptablyalter the benefits of the active compounds disclosed herein. The CTFACosmetic Ingredient Handbook, Second Edition (1992) describes a widevariety of non-limiting cosmetic and pharmaceutical ingredients commonlyused in the skin care industry, which are suitable for use in thecompositions disclosed herein. Examples of these ingredient classesinclude: abrasives, absorbents, aesthetic components such as fragrances,pigments, colorings/colorants, essential oils, skin sensates,astringents, etc. (e.g., clove oil, menthol, camphor, eucalyptus oil,eugenol, menthyl lactate, witch hazel distillate), anti-acne agents,anti-caking agents, antifoaming agents, antimicrobial agents (e.g.,iodopropyl butylcarbamate), antioxidants, binders, biological additives,buffering agents, bulking agents, chelating agents, chemical additives,colorants, cosmetic astringents, cosmetic biocides, denaturants, drugastringents, external analgesics, film formers or materials, e.g.,polymers, for aiding the film-forming properties and substantivity ofthe composition (e.g., copolymer of eicosene and vinyl pyrrolidone),opacifying agents, pH adjusters, propellants, reducing agents,sequestrants, skin-conditioning agents (e.g., humectants, includingmiscellaneous and occlusive), skin soothing and/or healing agents (e.g.,panthenol and derivatives (e.g., ethyl panthenol), aloe vera,pantothenic acid and its derivatives, allantoin, bisabolol, anddipotassium glycyrrhizinate), skin treating agents, thickeners, andvitamins and derivatives thereof.

In addition to the pharmaceutically effective amount of an agentdisclosed herein, the topical compositions also comprise adermatologically acceptable carrier. The phrase “dermatologicallyacceptable carrier”, as used herein, means that the carrier is suitablefor topical application to the skin, i.e., keratinous tissue, has goodaesthetic properties, is compatible with the active agents disclosedherein and any other components, and will not cause any safety ortoxicity concerns. A safe and effective amount of carrier is from about10% to about 99.99%, preferably from about 30% to about 99.9%, morepreferably from about 50% to about 98%, and most preferably from about60% to about 95% of the composition.

The carrier utilized in the disclosed compositions can be in a widevariety of forms. These include emulsion carriers, including, but notlimited to, oil-in-water, water-in-oil, water-in-oil-in-water, andoil-in-water-in-silicone emulsions, a cream, an ointment, an ophthalmicointment, an aqueous solution, a lotion or an aerosol. As will beunderstood by the skilled artisan, a given component will distributeprimarily into either the water or oil/silicone phase, depending on thewater solubility/dispersibility of the component in the composition.

Emulsions generally contain a pharmaceutically effective amount of anagent disclosed herein and a lipid or oil. Lipids and oils may bederived from animals, plants, or petroleum and may be natural orsynthetic (i.e., man-made). Preferred emulsions also contain ahumectant, such as glycerin. Emulsions will preferably further containfrom about 1% to about 10%, more preferably from about 2% to about 5%,of an emulsifier, based on the weight of the carrier. Emulsifiers may benonionic, anionic or cationic. Suitable emulsifiers are described in,for example, U.S. Pat. No. 3,755,560, issued to Dickert, et al. Aug. 28,1973; U.S. Pat. No. 4,421,769, issued to Dixon, et al. Dec. 20, 1983;and McCutcheon's Detergents and Emulsifiers, North American Edition,pages 317-324 (1986).

The emulsion may also contain an anti-foaming agent to minimize foamingupon application to the keratinous tissue. Anti-foaming agents includehigh molecular weight silicones and other materials well known in theart for such use.

Suitable emulsions may have a wide range of viscosities, depending onthe desired product form. Exemplary low viscosity emulsions, which arepreferred, have a viscosity of about 50 centistokes or less, morepreferably about 10 centistokes or less, most preferably about 5centistokes or less. The emulsion may also contain an anti-foaming agentto minimize foaming upon application to the keratinous tissue.Anti-foaming agents include high molecular weight silicones and othermaterials well known in the art for such use.

One type of emulsion is a water-in-silicone emulsion. Water-in-siliconeemulsions contain a continuous silicone phase and a dispersed aqueousphase. Preferred water-in-silicone emulsions as disclosed hereincomprise from about 1% to about 60%, preferably from about 5% to about40%, more preferably from about 10% to about 20%, by weight of acontinuous silicone phase. The continuous silicone phase exists as anexternal phase that contains or surrounds the discontinuous aqueousphase described hereinafter.

The continuous silicone phase may contain a polyorganosiloxane oil. Apreferred water-in-silicone emulsion system is formulated to provide anoxidatively stable vehicle for delivery of a pharmaceutically effectiveamount of an agent disclosed herein. The continuous silicone phase ofthese preferred emulsions comprises between about 50% and about 99.9% byweight of organopolysiloxane oil and less than about 50% by weight of anon-silicone oil. In an especially preferred embodiment, the continuoussilicone phase comprises at least about 50%, preferably from about 60%to about 99.9%, more preferably from about 70% to about 99.9%, and evenmore preferably from about 80% to about 99.9%, polyorganosiloxane oil byweight of the continuous silicone phase, and up to about 50%non-silicone oils, preferably less about 40%, more preferably less thanabout 30%, even more preferably less than about 10%, and most preferablyless than about 2%, by weight of the continuous silicone phase. Theseuseful emulsion systems may provide more oxidative stability overextended periods of time than comparable water-in-oil emulsionscontaining lower concentrations of the polyorganosiloxane oil.Concentrations of non-silicone oils in the continuous silicone phase areminimized or avoided altogether so as to possibly further enhanceoxidative stability of the active compounds disclosed herein in thecompositions. Water-in-silicone emulsions of this type are described inU.S. Pat. No. 5,691,380 to Mason et al., issued Nov. 25, 1997.

The organopolysiloxane oil for use in the composition may be volatile,non-volatile, or a mixture of volatile and non-volatile silicones. Theterm “nonvolatile” as used in this context refers to those siliconesthat are liquid under ambient conditions and have a flash point (underone atmospheric of pressure) of or greater than about 100° C. The term“volatile” as used in this context refers to all other silicone oils.Suitable organopolysiloxanes can be selected from a wide variety ofsilicones spanning a broad range of volatilities and viscosities.Examples of suitable organopolysiloxane oils include polyalkylsiloxanes,cyclic polyalkylsiloxanes, and polyalkylarylsiloxanes, which are knownto those skilled in the art and commercially available.

The continuous silicone phase may contain one or more non-silicone oils.Concentrations of non-silicone oils in the continuous silicone phase arepreferably minimized or avoided altogether so as to further enhanceoxidative stability of the pharmaceutically effective agent in thecompositions. Suitable non-silicone oils have a melting point of about25° C. or less under about one atmosphere of pressure. Examples ofnon-silicone oils suitable for use in the continuous silicone phase arethose well known in the chemical arts in topical personal care productsin the form of water-in-oil emulsions, e.g. mineral oil, vegetable oils,synthetic oils, semisynthetic oils, etc.

Useful topical compositions comprise from about 30% to about 90%, morepreferably from about 50% to about 85%, and most preferably from about70% to about 80% of a dispersed aqueous phase. In emulsion technology,the term “dispersed phase” is a term well-known to one skilled in theart which means that the phase exists as small particles or dropletsthat are suspended in and surrounded by a continuous phase. Thedispersed phase is also known as the internal or discontinuous phase.The dispersed aqueous phase is a dispersion of small aqueous particlesor droplets suspended in and surrounded by the continuous silicone phasedescribed hereinbefore. The aqueous phase can be water, or a combinationof water and one or more water soluble or dispersible ingredients.Nonlimiting examples of such optional ingredients include thickeners,acids, bases, salts, chelants, gums, water-soluble or dispersiblealcohols and polyols, buffers, preservatives, sunscreening agents,colorings, and the like.

Topical compositions typically comprise from about 25% to about 90%,preferably from about 40% to about 80%, more preferably from about 60%to about 80%, water in the dispersed aqueous phase by weight of thecomposition.

The water-in-silicone emulsions preferably comprise an emulsifier. In apreferred embodiment, the composition contains from about 0.1% to about10% emulsifier, more preferably from about 0.5% to about 7.5%, mostpreferably from about 1% to about 5%, emulsifier by weight of thecomposition. The emulsifier helps disperse and suspend the aqueous phasewithin the continuous silicone phase.

A wide variety of emulsifying agents can be employed herein to form thepreferred water-in-silicone emulsion. Known or conventional emulsifyingagents can be used in the composition, provided that the selectedemulsifying agent is chemically and physically compatible with essentialcomponents of the composition, and provides the desired dispersioncharacteristics. Suitable emulsifiers include silicone emulsifiers,e.g., organically modified organopolysiloxanes, also known to thoseskilled in the art as silicone surfactants, non-silicon-containingemulsifiers, and mixtures thereof, known by those skilled in the art foruse in topical personal care products.

Useful emulsifiers include a wide variety of silicone emulsifiers. Thesesilicone emulsifiers are typically organically modifiedorganopolysiloxanes, also known to those skilled in the art as siliconesurfactants. Suitable emulsifiers are described, for example, inMcCutcheon's Detergents and Emulsifiers, North American Edition (1986),published by Allured Publishing Corporation; U.S. Pat. No. 5,011,681 toCiotti et al., issued Apr. 30, 1991; U.S. Pat. No. 4,421,769 to Dixon etal., issued Dec. 20, 1983; and U.S. Pat. No. 3,755,560 to Dickert etal., issued Aug. 28, 1973.

Other preferred topical carriers include oil-in-water emulsions, havinga continuous aqueous phase and a hydrophobic, water-insoluble phase(“oil phase”) dispersed therein. Examples of suitable carrierscomprising oil-in-water emulsions are described in U.S. Pat. No.5,073,371 to Turner, D. J. et al., issued Dec. 17, 1991, and U.S. Pat.No. 5,073,372, to Turner, D. J. et al., issued Dec. 17, 1991. Anespecially preferred oil-in-water emulsion, containing a structuringagent, hydrophilic surfactant and water, is described in detailhereinafter.

A preferred oil-in-water emulsion comprises a structuring agent toassist in the formation of a liquid crystalline gel network structure.Without being limited by theory, it is believed that the structuringagent assists in providing rheological characteristics to thecomposition which contribute to the stability of the composition. Thestructuring agent may also function as an emulsifier or surfactant.Preferred compositions comprise from about 0.5% to about 20%, morepreferably from about 1% to about 10%, most preferably from about 1% toabout 5%, by weight of the composition, of a structuring agent. Thepreferred structuring agents are selected from the group consisting ofstearic acid, palmitic acid, stearyl alcohol, cetyl alcohol, behenylalcohol, stearic; acid, palmitic acid, the polyethylene glycol ether ofstearyl alcohol having an average of about 1 to about 21 ethylene oxideunits, the polyethylene glycol ether of cetyl alcohol having an averageof about 1 to about 5 ethylene oxide units, and mixtures thereof.

The preferred oil-in-water emulsions comprise from about 0.05% to about10%, preferably from about 1% to about 6%, and more preferably fromabout 1% to about 3% of at least one hydrophilic surfactant which candisperse the hydrophobic materials in the water phase (percentages byweight of the topical carrier). The surfactant, at a minimum, must behydrophilic enough to disperse in water. Suitable surfactants includeany of a wide variety of known cationic, anionic, zwitterionic, andamphoteric surfactants. See, McCutcheon's. Detergents and Emulsifiers,North American Edition (1986), published by Allured PublishingCorporation; U.S. Pat. No. 5,011,681 to Ciotti et al., issued Apr. 30,1991; U.S. Pat. No. 4,421,769 to Dixon et al. issued Dec. 20, 1983; andU.S. Pat. No. 3,755,560. The exact surfactant chosen depends upon the pHof the composition and the other components present. Preferred arecationic surfactants, especially dialkyl quaternary ammonium compounds,examples of which are described in U.S. Pat. No. 5,151,209 to McCall etal. issued Sep. 29, 1992; U.S. Pat. No. 5,151,210 to Steuri et al.issued Sep. 29, 1992; U.S. Pat. No. 5,120,532; U.S. Pat. No. 4,387,090;U.S. Pat. No. 3,155,591; U.S. Pat. No. 3,929,678; U.S. Pat. No.3,959,461; McCutcheon's, Detergents & Emulsifiers (North Americanedition 1979) M.C. Publishing Co.; and Schwartz, et al., Surface ActiveAgents, Their chemistry and Technology, New York: IntersciencePublishers, 1949.

Alternatively, other useful cationic emulsifiers include amino-amides.Nonlimiting examples of these cationic emulsifiers includestearamidopropyl PG-dimonium chloride phosphate, behenamidopropyl PGdimonium chloride, stearamidopropyl ethyldimonium ethosulfate,stearamidopropyl dimethyl (myristyl acetate) ammonium chloride,stearamidopropyl dimethyl cetearyl ammonium tosylate, stearamidopropyldimethyl ammonium chloride, stearamidopropyl dimethyl ammonium lactate,and mixtures thereof.

A wide variety of anionic surfactants are also useful herein. See, e.g.,U.S. Pat. No. 3,929,678, to Laughlin et al., issued Dec. 30, 1975. Inaddition, amphoteric and zwitterionic surfactants are also usefulherein.

The preferred oil-in-water emulsion comprises from about 25% to about98%, preferably from about 65% to about 95%, more preferably from about70% to about 90% water by weight of the topical carrier.

The hydrophobic phase is dispersed in the continuous aqueous phase. Thehydrophobic phase may contain water insoluble or partially solublematerials such as are known in the art, including but not limited to thesilicones described herein in reference to silicone-in-water emulsions,and other oils and lipids such as described above in reference toemulsions.

The topical compositions disclosed herein, including but not limited tolotions and creams, may comprise a dermatologically acceptableemollient. Such compositions preferably contain from about 2% to about50% of the emollient. As used herein, “emollient” refers to a materialuseful for the prevention or relief of dryness, as well as for theprotection of the skin. A wide variety of suitable emollients are knownand may be used herein. See, e.g., Sagarin, Cosmetics, Science andTechnology, 2nd Edition, Vol. 1, pp. 3243 (1972), which containsnumerous examples of materials suitable as an emollient. A preferredemollient is glycerin. Glycerin is preferably used in an amount of fromor about 0.001 to or about 20%, more preferably from or about 0.01 to orabout 10%, most preferably from or about 0.1 to or about 5%, e.g., 3%.

Lotions and creams according to the embodiments disclosed hereingenerally comprise a solution carrier system and one or more emollients.Lotions typically comprise from about 1% to about 20%, preferably fromabout 5% to about 10% of emollient; from about 50% to about 90%,preferably from about 60% to about 80% water; and a pharmaceuticallyeffective amount of an agent described herein. A cream typicallycomprises from about 5% to about 50%, preferably from about 10% to about20% of emollient; from about 45% to about 85%, preferably from about 50%to about 75% water; and a pharmaceutically effective amount of an agentdescribed herein.

Ointments may comprise a simple carrier base of animal or vegetable oilsor semi-solid hydrocarbons (oleaginous); absorption ointment bases whichabsorb water to form emulsions; or water soluble carriers, e.g., a watersoluble solution carrier. Ointments may further comprise a thickeningagent, such as described in Sagarin, Cosmetics, Science and Technology,2nd Edition, Vol. 1, pp. 72-73 (1972), incorporated herein by reference,and/or an emollient. For example, an ointment may comprise from about'2%to about 10% of an emollient; from about 0.1% to about 2% of athickening agent; and a pharmaceutically effective amount of an agentdescribed herein.

By way of non-limiting example, 1000 g of topical cream is prepared fromthe following types and amounts of ingredients: a pharmaceuticallyeffective amount of an agent disclosed herein, tegacid regular (150 g)(a self-emulsifying glyceryl monostearate from Goldschmidt ChemicalCorporation, New York, N.Y.), polysorbate 80 (50 g), spermaceti (100 g),propylene glycol (50 g), methylparaben (1 g), and deionized water insufficient quantity to reach 1000 gm. The tegacid and spermaceti aremelted together at a temperature of 70-80° C. The methylparaben isdissolved in about 500 g of water and the propylene glycol, polysorbate80, and 6-amino-1,2-dihydro-1-hydroxy-2-imino-4-piperidinopyrimidinefree base are added in turn, maintaining a temperature of 75-80° C. Themethylparaben mixture is added slowly to the tegacid and spermacetimelt, with constant stirring. The addition is continued for at least 30minutes with additional stirring until the temperature has dropped to40-45° C. Finally, sufficient water is added to bring the final weightto 1000 g and the preparation stirred to maintain homogeneity untilcooled and congealed.

By way of non-limiting example, 1000 g of a topical ointment is preparedfrom the following types and amounts of ingredients: a pharmaceuticallyeffective amount of an agent disclosed herein, zinc oxide (50 g),calamine (50 g), liquid petrolatum (heavy) (250 g), wool fat (200 g),and enough white petrolatum to reach 1000 g. Briefly, the whitepetrolatum and wool fat are melted and 100 g of liquid petrolatum addedthereto. The pharmaceutically effective amount of an agent disclosedherein, zinc oxide, and calamine are added to the remaining liquidpetrolatum and the mixture milled until the powders are finely dividedand uniformly dispersed. The mixture is stirred into the whitepetrolatum, melted and cooled with stirring until the ointment congeals.

By way of non-limiting example, 1000 g of an ointment, e.g., anophthalmic ointment, containing a pharmaceutically effective amount ofan agent disclosed herein is prepared from the following types andamounts of ingredients: a pharmaceutically effective amount of an agentdisclosed herein, light liquid petrolatum (250 g), wool fat (200 g), andenough white petrolatum to reach 1000 g. Briefly, the pharmaceuticallyeffective amount of an agent disclosed herein is finely divided andadded to the light liquid petrolatum. The wool fat and white petrolatumare melted together, strained, and the temperature adjusted to 45-50° C.The liquid petrolatum slurry is added, and the ointment stirred untilcongealed.

By way of non-limiting example, 1000 ml of an aqueous solutioncontaining a pharmaceutically effective amount of an agent disclosedherein is prepared from the following types and amounts of ingredients:a pharmaceutically effective amount of an agent disclosed herein,polyethylene glycol 4000 (120 g) myristyl-gamma-picolinium chloride (0.2g), polyvinylpyrrolidone (1 g), and enough deionized water to reach 1000milliliters. Briefly, the ingredients are dissolved in the water and theresulting solution is sterilized by filtration.

By way of non-limiting example, 1000 g of lotion containing apharmaceutically effective amount of an agent disclosed herein isprepared from the following types and amounts of ingredients: apharmaceutically effective amount of an agent disclosed herein, N-methylpyrolidone (40 g), and enough propylene glycol to reach 1000 g.

By way of non-limiting example, an aerosol containing a pharmaceuticallyeffective amount of an agent disclosed herein is prepared from thefollowing types and amounts of materials: a pharmaceutically effectiveamount of an agent disclosed herein, absolute alcohol (4.37 g),Dichlorodifluoroethane (1.43 g) and dichlorotetrafluoroethane (5.70 g).Briefly, the pharmaceutically effective amount of an agent disclosedherein is dissolved in the absolute alcohol and the resulting solutionfiltered to remove particles and lint. This solution is chilled to about−30° C. Then, to this is added the chilled mixture ofdichlorodifluoromethane and dichlorotetrafluoroethane.

For oral administration, Gelatin capsules or liquid-filled soft gelatincapsules can contain the active ingredient and powdered or liquidcarriers, such as lactose, lecithin starch, cellulose derivatives,magnesium stearate, stearic acid, and the like. Similar diluents can beused to make compressed tablets. Both tablets and capsules can bemanufactured as sustained release products to provide for continuousrelease of medication over a period of hours. Compressed tablets can besugar-coated or film-coated to mask any unpleasant taste and to protectthe tablet from the atmosphere, or enteric-coated for selective,targeted disintegration in the gastrointestinal tract. Liquid dosageforms for oral administration can contain coloring and/or flavoring toincrease patient acceptance.

In general, sterile water, oil, saline, aqueous dextrose (glucose),polysorbate and related sugar solutions and glycols such as propyleneglycol or polyethylene glycols, are suitable carriers for parenteralsolutions. Solutions or emulsions for parenteral administrationpreferably contain about 5-15% polysorbate 80 or lecithin, suitablestabilizing agents and, if necessary, buffer substances. Antioxidizingagents such as, but not limited to, sodium bisulfite, sodium sulfite, orascorbic acid, either alone or combined, are suitable stabilizingagents. Also useful are citric acid and its salts, and sodium EDTA. Inaddition, parenteral solutions can contain preservatives including, butnot limited to, benzalkonium chloride, methyl- or propyl-paraben, andchlorobutanol.

As will be understood by those in the art, the compositions andpharmaceutical compositions may be provided in the form of a kit. Kitscomprise one or more specific compositions and/or pharmaceuticalcompositions disclosed herein. Optionally, the kit further containsprinted instructions as a label or package insert directing the use ofsuch reagents to modify skin pigmentation, i.e., to lighten skin asappropriate to the particular included composition. These compounds areprovided in a container designed to prevent contamination, minimizeevaporation or drying of the composition, etc. The compounds may or maynot be provided in a preset unit dose or usage amount.

The following formulation examples illustrate representativepharmaceutical compositions that may be prepared in accordance with theembodiments disclosed herein, but are not meant to be limited to thefollowing pharmaceutical compositions.

Formulation 1—Tablets

An effective amount of a compound as in Formulae I-VIIc may be admixedas a dry powder with a dry gelatin binder in an approximate 1:2 weightratio. A minor amount of magnesium stearate may be added as a lubricant.The mixture may then be formed into 240-270 mg tablets (80-90 mg ofactive compound per tablet) in a tablet press.

Formulation 2—Capsules

An effective amount of a compound as in Formulae I-VIIc may be admixedas a dry powder with a starch diluent in an approximate 1:1 weightratio. The mixture may then be filled into 250 mg capsules (125 mg ofactive compound per capsule).

Formulation 3—Liquid

An effective amount of a compound as in Formulae I-VIIc (125 mg) may beadmixed with sucrose (1.75 g) and xanthan gum (4 mg) and the resultantmixture may be blended, passed through a No. 10 mesh U.S. sieve, andthen mixed with a previously made solution of microcrystalline celluloseand sodium carboxymethyl cellulose (11:89, 50 mg) in water. Sodiumbenzoate (10 mg), flavor, and color are diluted with water and addedwith stirring. Sufficient water may then be added to produce a totalvolume of 5 mL.

Formulation 4—Tablets

An effective amount of a compound as in Formulae I-VIIc may be admixedas a dry powder with a dry gelatin binder in an approximate 1:2 weightratio. A minor amount of magnesium stearate may then be added as alubricant. The mixture may then be formed into 450-900 mg tablets(150-300 mg of active compound) in a tablet press.

Formulation 5—Injection

An effective amount of a compound as in Formulae I-VIIc may be dissolvedor suspended in a buffered sterile saline injectable aqueous medium to aconcentration of approximately 5 mg/mL.

Formulation 6—Topical

Stearyl alcohol (250 g) and a white petrolatum (250 g) may be melted atabout 75° C. and then a mixture of a compound as in Formulae I-VIIc(10-50 g of active compound) methylparaben (0.25 g), propylparaben (0.15g), sodium lauryl sulfate (10 g), and propylene glycol (120 g) dissolvedin water (about 370 g) may then be added and the resulting mixture isstirred until it congeals.

General Synthetic Procedures

The benzopyran compounds as in Formulae I-VIIc which comprise variousknown drugs or drug like molecules can be purchased from commercialsources and tested for their activities. The benzopyran compounds whichare not commercially available can be prepared from readily availablestarting materials using various general methods and procedures known inthe art.

Additionally, as will be apparent to those skilled in the art,conventional protecting groups may be necessary to prevent certainfunctional groups from undergoing undesired reactions. The choice of asuitable protecting group for a particular functional group as well assuitable conditions for protection and deprotection are well known inthe art. For example, numerous protecting groups, and their introductionand removal, are described in T. W. Greene and P. G. M. Wuts, ProtectingGroups in Organic Synthesis, Second Edition, Wiley, New York, 1991, andreferences cited therein.

EXAMPLES Example 1 Screening of Compounds in Cultured Murine Melanocytes

The Spectrum Collection library consisting of 2000 drug compounds ornatural products represents a source for the identification of compoundsuseful in the present invention. The library may be screened to identifynovel pigmentation inhibitors in cultured murine melanocytes (melan-a).Compounds are dissolved in dimethylsulfoxide (DMSO) to a finalconcentration of 10 mM. Screening is performed with cultured melanocytesin 24-well plates followed by melanin assay (see below). A minimumchange of 50% in melanin formation is established as significant for apigmentation inhibitor. DMSO may be used as a negative control and thewidely used depigmenting agent, hydroquinone, may be used as a positivecontrol on every plate. Primary screening is performed at a finalconcentration of 1 μM and potential candidates from the primaryscreening are reconfirmed in duplicate at final concentrations of 1 and5 μM.

Melan-a cells are plated at 5×10⁴ cells per well in 1 ml of culturemedia in 24-well plates the day before adding the library compounds. Allcompounds are added at the indicated final concentrations. Cells areharvested after 72 hours of incubation, and the melanin assay isperformed.

For further test and mechanism of action studies, the compounds may bepurchased from Sigma, MicroSource or other known suppliers. Thecompounds are dissolved in dimethylsulfoxide (DMSO) to a finalconcentration of 10 mM, and are tested for their effect on melaninsynthesis at the indicated final concentrations.

Example 2 Melanin Assay

For the primary and secondary screening, cells were harvested anddissolved in 200 μl of 2N NaOH in 20% DMSO at 70° C. A 180-μl aliquot ofthe resulting solution was measured for absorbance at 490 nm.

Cells are harvested in extraction buffer (1% Triton X-100, 50 mM Tris, 2mM EDTA, 150 mM NaCl, pH 7.5) containing a complete protease inhibitorcocktail (Roche). The lysates were centrifuged at 14,000 rpm for 10minutes at 4° C. BCA protein assay kit (Pierce) was used to measure theprotein concentrations of the supernatants, and bovine serum albumin wasused as a standard. The remaining pellets were incubated with 100 μlethanol-ether (1:1) for 10 minutes at room temperature. After removingthe ethanol-ether, the pellets were dissolved in 200 μl of 2N NaOH in20% DMSO at 70° C. A 180-μl aliquot of the resulting solution wasmeasured for absorbance at 490 nm. The melanin contents were normalizedto the total amount of protein.

The compounds, their structures, inhibition data expressed as % ofcontrol remaining, are set forth in FIG. 1 and are shown in Table 1,below.

TABLE 1 Activity Data for Compounds Useful as Melanogenesis Modifiers %of % of control control melanin melanin remaining remaining after aftertreatment treatment ID Name Structure @ 1 μM @ 5 μM 1 Osajin

99 87 2 Osajin-4′methyl ether

99 70 3 Pomiferin

53 — 4 Pomiferin-3′,4′-dimethyl ether

80 50 5 Warangalone

100  78

Example 3 MTT Proliferation Assay

The following MTT cell proliferation assay was conducted to furtherassess the activity of certain of the compounds in accordance with thepresent invention.

Accordingly, melan-a cells were plated, allowed to attach overnight thendosed with the appropriate concentration of the respective compound.Each concentration was tested in triplicate. After 72 hours, plates wereinverted and gently tapped to remove all the media. Fresh mediacontaining MTT reagent (CellTiter, Promega, Madison, Wis.) was added andincubated per manufacturer's instructions. Absorbance was then measuredat 490 nm. Values were corrected by subtracting the blank (no cells inthe well), and viability was expressed as a function of the viability ofcells treated with vehicle alone. The results of all compounds testedare presented in FIG. 2, and individual test results as to Osajin,Osajin-4′-methyl ether, Pomiferin, Pomiferin-3′,4′-dimethyl ether, andWarangalone, are presented in FIGS. 3-7, respectively.

From the results, it can be seen that the methyl ethers of osajin andpomiferin are less toxic than the compounds osajin and pomiferin alone.

Example 4 MelanoDerm™ Pigmentation Assay

The compounds of the invention may be tested in the Melanoderm™pigmentation assay, to confirm and demonstrate their activity asinhibitors in a setting that replicates in vivo conditions. MelanoDerm™,made by MatTek Corp., is a viable reconstituted three-dimensional humanskin equivalent containing normal melanocytes and keratinocytes that arederived from African-American (MEL-B), Asian (MEL-A) or caucasian(MEL-C) donors. Both MEL-A and MEL-B tissues are used in the study, andthey are maintained in the NMM-113 medium as recommended by themanufacturer.

The test compound is dissolved in 30% ethanol:70% propylene glycol to afinal concentration of 1.0 mm (equal to 356.6 μg/ml), and this ismaintained constant and used on all samples tested. A 25 μl of itsaliquot is applied topically to the MelanoDerm™ tissue (MEL-B) on Days0, 1, 3, 6, 8 and 10. The MelanoDerm™ tissues are fed every other daywith 5 ml fresh NMM-113. Prior to each application, the tissues arewashed with 1 ml PBS to remove any residual test compound. Tissues arefixed on Days 10 and 13 for microscopic analysis and histologicalevaluation. In addition, duplicate tissues are frozen on Days 10 and 13for the melanin assay.

Similar experiments may be performed on Asian skin equivalent (MEL-A)except: the treatments are applied on Days 0, 1, 3, 6, 8, 10 and 13.Tissues are taken out on Days 13 and 16 for the various assays. 30%ethanol:70% propylene glycol is used as a negative control and thewell-known pigmentation inhibitor, arbutin (at concentration of 3mg/ml), may be used as a positive control.

The experiments are repeated twice on both MEL-A and MEL-B tissues fromdifferent lots to make sure that the results are reproducible (study 1or 2). For each experiment, six tissues are treated with a compound orextract of the invention, and six were treated with vesicle (30%ethanol:70% PEG) or arbutin if applicable. For MEL-B, on Day 10, threetissues under each treatment condition are taken out, and one was usedfor histological studies and the other two are used for the melaninassay. The same protocol is followed with the MEL-B samples after 13days' treatment and MEL-A after either 13 or 16 days' treatments.

For the histological studies:

Procedure 1: the effects of the inventive compounds or extract onmelanin synthesis in MEL-A or B are evaluated by light microscopy (viewsfrom the top surface of the tissue).Procedure 2: the distribution of melanin in the treated-MEL-A or B isaccessed by image analysis using Fontana-Masson stained histologicalsections (views from the side of the tissue).

For the melanin tissues, the melanin content of each individual tissueis determined, and the final data show the average melanin content of 2tissues treated under identical conditions.

Example 5 Melanin Inhibition by the Extract Derived from the Fruit ofMaclura Pomifera

Melan-a cells are plated at 5×10⁴ cells per well in 1 ml of culturemedia in 24-well plates the day before adding an extract made from apowder prepared from the fruit of Maclura pomifera. Ethanol (70%) isused as control and the extract derived from the fruit of Maclurapomifera is diluted in cell culture media at the indicatedconcentrations. Cells are harvested after 72 hours of incubation, andspectrophotometric melanin assay is performed on cell pellets. Themelanin contents are normalized to the total amount of protein. Cellviability is determined by using the CellTiter 96 aqueous nonradioactivecell proliferation assay.

Those compounds which are found to reduce pigmentation (melanogenesismodifiers or inhibitors; see Table 1) and compositions thereof can beused as topical agents for hair, fur, and/or feather lightening asrequired. A melanogenesis inhibitor of the invention or a compositionthereof may be applied to sites of hyperpigmentation including, withoutlimitation, age spots, freckles, and chloasma. For some individuals,body lightening or whitening of larger skin zones is a cosmeticobjective that can be achieved with a more generalized application of amelanogenesis inhibitor of the invention or a composition thereof.

While certain of the preferred embodiments have been described andspecifically exemplified above, it is not intended that the invention belimited to such embodiments. Various modifications may be made theretowithout departing from the scope and spirit of the present invention, asset forth in the following claims.

From the foregoing description, various modifications and changes in thecompositions and methods of this invention will occur to those skilledin the art. All such modifications coming within the scope of theappended claims are intended to be included therein.

All publications, including but not limited to patents and patentapplications, cited in this specification are herein incorporated byreference as if each individual publication were specifically andindividually indicated to be incorporated by reference herein as thoughfully set forth.

The chemical names of compounds given in this application were generatedusing various commercially available chemical naming software toolsincluding MDL's ISIS Draw Autonom Software tool, and were not verified.Particularly, in the event of inconsistency, the depicted structuregoverns.

1. A method for inhibiting melanogenesis or a method for promoting skinlightening comprising administering to a mammal an effective amount of acompound of formula I:

wherein R³ is selected from H, halo, substituted or unsubstituted alkyl,substituted or unsubstituted alkenyl, or substituted or unsubstitutedaryl; and substituted or unsubstituted heteroaryl; R⁴ is selected fromH, halo, hydroxy, alkoxy, alkenyloxy, substituted or unsubstitutedalkyl, substituted or unsubstituted alkenyl, and substituted orunsubstituted phenyl; each R⁵, R⁶, and R⁸ is independently selected fromH, halo, hydroxy, alkoxy, alkenyloxy, substituted or unsubstitutedalkyl, substituted or unsubstituted alkenyl, and substituted orunsubstituted phenyl; R⁷ is selected from H, halo, hydroxy, alkoxy,alkenyloxy, substituted or unsubstituted alkyl, substituted orunsubstituted alkenyl, or heterocycloalkyl; or R⁷ is —P(═O)(alkoxy)₂, or—P(═S)(alkoxy)₂; or R⁶ and R⁷ or R⁷ and R⁸ are joined to form a 5- or6-membered heterocycloalkyl or heterocycloalkenyl; and theheterocycloalkyl or heterocycloalkenyl is unsubstituted or substitutedwith one more groups selected from alkyl, alkenyl, hydroxyalkyl,acyloxyalkyl, hydroxy, and alkoxy; or pharmaceutically acceptable salts,solvates, isomers, tautomers, metabolites, analogs, isotopic variants orprodrugs thereof.
 2. The method of claim 1 wherein the compound is offormula I; and R⁷ is selected from H, substituted or unsubstitutedalkyl, and substituted or unsubstituted alkenyl.
 3. The method of eitherof claim 1 or 2, wherein the compound is of formula I; and R³ is H, Cl,alkyl, or substituted or unsubstituted phenyl.
 4. The method of eitherof claim 1 or 2, wherein the compound is of formula I; and R³ is Cl, Me,phenyl, 4-hydroxyphenyl, or 4-methoxyphenyl.
 5. The method of any one ofclaims 1-4, wherein the compound is of formula I; and R⁴ is H, Cl,alkyl, or substituted or unsubstituted phenyl.
 6. The method of any oneof claims 1-4, wherein the compound is of formula I; and R⁴ is H, Cl,Me, phenyl, or 4-methoxyphenyl.
 7. The method of any one of claims 1-6,wherein the compound is of formula I; and R⁵ is H, Cl, alkyl, hydroxy,or alkoxy.
 8. The method of any one of claims 1-6, wherein the compoundis of formula I; and R⁵ is H, Cl, Me, OH, or OMe.
 9. The method of anyone of claims 1-8, wherein the compound is of formula I; and R⁶ is H,Cl, alkyl, alkenyl, hydroxy, alkoxy, or alkenyloxy.
 10. The method ofany one of claims 1-8, wherein the compound is of formula I; and R⁶ isH, Cl, OH, OMe, 3-methylbut-2-enyl, or 3-methylbut-2-enyloxy.
 11. Themethod of any one of claims 1-8, wherein the compound is of formula I;and R⁶ is H, or OMe.
 12. The method of any one of claims 1-11, whereinthe compound is of formula I; and R⁸ is H, Cl, alkyl, alkenyl, hydroxy,alkoxy, or alkenyloxy.
 13. The method of any one of claims 1-11, whereinthe compound is of formula I; and R⁸ is H, Cl, OH, OMe,3-methylbut-2-enyl, or 3-methylbut-2-enyloxy.
 14. The method of any oneof claims 1-11, wherein the compound is of formula I; and R⁸ is OH, OMe,or 3-methylbut-2-enyl.
 15. The method of any one of claims 1-14, whereinthe compound is of formula I; and R⁷ is H, Me, 3-methylbut-2-enyl,P(═O)(OEt)₂, P(═S)(OEt)₂, or 6-hydroxymethyl-3,4,5-trihydroxypyran-2-yl.16. The method of claim 1 wherein the compound is of formula I; each R³,R⁴, R⁵, R⁶ is H; R⁷ is as in claim 1; and R⁸ is substituted orunsubstituted alkenyl.
 17. The method of claim 16, wherein R⁸ is3-methylbut-2-enyl.
 18. The method of claim 1 wherein the compound is offormula I; R⁴, R⁵, R⁶, R⁷ and R⁸ are as in claim 1; and R³ is Cl. 19.The method of any one of claims 16-18, wherein R⁷ is H, Me,3-methylbut-2-enyl, P(═O)(OEt)₂, P(═S)(OEt)₂, or6-hydroxymethyl-3,4,5-trihydroxypyran-2-yl.
 20. The method of any one ofclaims 16-18, wherein R⁷ is Me, or P(═S)(OEt)₂.
 21. The method of anyone of claims 16-18, wherein R⁷ is Me.
 22. The method of claim 1 whereinthe compound is of formula I; and R⁶ and R⁷ or R⁷ and R⁸ are joined toform a 5- or 6-membered heterocycloalkyl or heterocycloalkenyl; and theheterocycloalkyl or heterocycloalkenyl is unsubstituted or substitutedwith one more groups selected from alkyl, alkenyl, hydroxyalkyl,acyloxyalkyl, hydroxy, and alkoxy.
 23. The method of claim 1 wherein thecompound is of formula IIa, IIb, IIc, or IId:

or a pharmaceutically acceptable salt, solvate or prodrug thereof, andstereoisomers, tautomers and isotopic variants thereof; and wherein R⁴,R⁵, and R⁶ are as in claim 1; R³ is selected from halo, substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, orsubstituted or unsubstituted phenyl; R⁸ is selected from H, halo,hydroxy, alkoxy, alkenyloxy, substituted or unsubstituted alkyl,substituted or unsubstituted alkenyl, or substituted or unsubstitutedphenyl; and each R^(6a), R^(7a), R^(7b), and R^(8a) is independentlyselected from H, alkyl, hydroxyalkyl, or alkenyl.
 24. The method ofclaim 1 wherein the compound is of formula IIIa, IIIb, IIIc or IIId:

or a pharmaceutically acceptable salt, solvate or prodrug thereof, andstereoisomers, tautomers and isotopic variants thereof; and wherein R⁴,R⁵, and R⁶ are as in claim 1; R³ is selected from halo, substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, orsubstituted or unsubstituted phenyl; R⁸ is selected from H, halo,hydroxy, alkoxy, alkenyloxy, substituted or unsubstituted alkyl,substituted or unsubstituted alkenyl, or substituted or unsubstitutedphenyl; and each R^(6a), R^(7a) and R^(7b) is independently selectedfrom H, alkyl, hydroxyalkyl, or alkenyl.
 25. The method of claim 1wherein the compound is of formula IV:

or a pharmaceutically acceptable salt, solvate or prodrug thereof, andstereoisomers, tautomers and isotopic variants thereof; and wherein R⁴,and R⁵ are as in claim 1; R³ is selected from halo, substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, orsubstituted or unsubstituted phenyl; R⁸ is selected from H, halo,hydroxy, alkoxy, alkenyloxy, substituted or unsubstituted alkyl,substituted or unsubstituted alkenyl, or substituted or unsubstitutedphenyl; and each R^(6a) and R^(7a) is independently selected from H,alkyl, or alkenyl.
 26. The method of any one of claims 1-25, wherein R⁴is H, Cl, alkyl, hydroxy, alkoxy, or substituted or unsubstitutedphenyl.
 27. The method of any one of claims 1-25, wherein R⁴ is H, Me,OH, OMe, or 4-methoxyphenyl.
 28. The method of any one of claims 1-25,wherein R⁴ is H.
 29. The method of any one of claims 23-28, whereinR^(6a) is H or Me.
 30. The method of any one of claims 23-28, whereinR^(6a) is H.
 31. The method of any one of claims 23-30, wherein R^(7a)is H or Me.
 32. The method of any one of claims 23-31, wherein R^(7b) isH or Me.
 33. The method of any one of claims 23-30, wherein each R^(7a)and R^(7b) is H or Me.
 34. The method of any one of claims 23-30,wherein each R^(7a) and R^(7b) is Me.
 35. The method of any one ofclaims 23-25 wherein R^(8a) is H or Me.
 36. The method of claim 1wherein the compound is of formula Va, or Vb:

or a pharmaceutically acceptable salt, solvate or prodrug thereof, andstereoisomers, tautomers and isotopic variants thereof; and wherein R⁴,R⁵, and R⁶ are as in claim 1; R³ is selected from halo, substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, orsubstituted or unsubstituted phenyl; R⁸ is selected from H, halo,hydroxy, alkoxy, alkenyloxy, substituted or unsubstituted alkyl,substituted or unsubstituted alkenyl, or substituted or unsubstitutedphenyl.
 37. The method of any one of claims 1-36, wherein R⁵ is H, Cl,alkyl, hydroxy, or alkoxy.
 38. The method of any one of claims 1-36,wherein R⁵ is H, Cl, Me, OH, or OMe.
 39. The method of any one of claims1-36, wherein R⁵ is OH.
 40. The method of any one of claims 1-39 whereinR⁸ is H, Cl, alkyl, alkenyl, hydroxy, alkoxy, or alkenyloxy.
 41. Themethod of any one of claims 1-39 wherein R⁸ is H, Cl, OH, OMe,3-methylbut-2-enyl, or 3-methylbut-2-enyloxy.
 42. The method of any oneof claims 1-39 wherein R⁸ is 3-methylbut-2-enyl.
 43. The method of anyone of claims 1-39 wherein R⁶ is H, Cl, alkyl, alkenyl, hydroxy, alkoxy,or alkenyloxy.
 44. The method of any one of claims 1-39 wherein R⁶ is H,Cl, OH, OMe, 3-methylbut-2-enyl, or 3-methylbut-2-enyloxy.
 45. Themethod of any one of claims 1-39 wherein R⁶ is 3-methylbut-2-enyl. 46.The method of claim 1 wherein the compound is of formula VIa, or VIb:

or a pharmaceutically acceptable salt, solvate or prodrug thereof, andstereoisomers, tautomers and isotopic variants thereof; and wherein R³is selected from halo, substituted or unsubstituted alkyl, substitutedor unsubstituted alkenyl, or substituted or unsubstituted phenyl. 47.The method of any one of claims 1-46, wherein R³ is Cl, alkyl, orsubstituted or unsubstituted phenyl.
 48. The method of any one of claims1-46, wherein R³ is Me, phenyl, 4-hydroxyphenyl, 3,4-dihydroxyphenyl,4-methoxyphenyl, or 3,4-dimethoxyphenyl.
 49. The method of claim 1wherein the compound is of formula VIIa, VIIb, or VIIc:

or a pharmaceutically acceptable salt, solvate or prodrug thereof, andstereoisomers, tautomers and isotopic variants thereof.
 50. The methodof claim 1, wherein the compound is osajin-4′ methylether, orpomiferin-3′,4′-dimethyl ether.
 51. The method of claim 1, wherein thecompound is warangalone or warangalone-4′-methylether.
 52. The method ofclaim 1, further comprising an additional active agent.
 53. The methodof claim 52, wherein the additional active agent is a pharmacologicalagent, a skin brightening agent or a skin lightening agent.
 54. Themethod of claim 1, wherein the effective amount of melanogenesisinhibitor is from about 0.01 mg to about 100 mg.
 55. The method of claim1, wherein the effective amount of melanogenesis inhibitor is from about0.1 mg to about 10 mg.
 56. The method of claim 1, wherein themelanogenesis inhibitor inhibits melanogenesis by about 10%.
 57. Themethod of claim 1, wherein the melanogenesis inhibitor inhibitsmelanogenesis by about 25% or about 50%.
 58. A composition forinhibiting melanogenesis comprising a pharmaceutically acceptablecarrier and a pharmaceutically effective amount of a compound of any oneof claims 1-51.
 59. The composition of claim 58, wherein the carrier isa parenteral, oral or topical carrier.
 60. The composition of claim 58,wherein the carrier is a topical carrier.
 61. The composition of claim58, wherein the effective amount of a melanogenesis inhibitor is fromabout 0.01 mg to about 100 mg.
 62. The composition of claim 58, whereinthe effective amount of a melanogenesis inhibitor is from about 0.1 mgto about 10 mg.
 63. The composition of claim 58, wherein themelanogenesis inhibitor inhibits melanogenesis by about 10%.
 64. Thecomposition of claim 58, wherein the melanogenesis inhibitor inhibitsmelanogenesis by about 25% or about 50%.
 65. A topical formulationcomprising a composition for cosmetic or dermatological use, saidcomposition comprising a compound of any one of claims 1-51, and anacceptable carrier.
 66. A method for preventing, treating, amelioratingor managing a disease or condition involving undesired or aberrantmelanogenesis, which comprises administering to a patient in need ordesirous of such prevention, treatment, amelioration or management, aprophylactically or therapeutically effective melanogenesis-inhibitingamount of a compound of any one of claims 1-51.
 67. The method of claim66, wherein the compound or composition is administered to lighten orreduce pigmentation levels.
 68. The method of claim 66, wherein thecompound or composition is administered to lighten or reducepigmentation levels of hyperpigmented sites on skin.
 69. A method foraltering or restoring pigmentation in mammalian skin, hair, wool or furcomprising administering to the mammalian skin, hair, wool or fur anamount of a composition comprising: a) an amount, which is effective toalter or restore pigmentation in mammalian skin, hair, wool or fur, ofone or more compounds claim 1; and b) a suitable carrier, wherein theamount is effective to alter or restore pigmentation in mammalian skin,hair, wool or fur.
 70. The method of claim 69, wherein the compound is amelanogenesis inhibitor.
 71. The method of claim 69, wherein themelanogenesis inhibitor is administered to lighten or reducepigmentation levels of the mammalian skin, hair, wool or fur.
 72. Acombination of a compound as defined in any one of claims 1-51, and alike-acting agent.
 73. The combination of claim 72, wherein said likeacting agent is selected from a cosmetic ingredient and apharmacologically active agent.
 74. The combination of claim 73, whereinthe cosmetic ingredient is a skin lightener or a skin-brightener. 75.The combination of claim 73, wherein said pharmacologically active agentis selected from another melanogenesis inhibitor.
 76. A method forpreventing, treating, ameliorating or managing a disease or conditioninvolving undesired or aberrant melanogenesis, which comprisesadministering to a patient in need or desirous of such prevention,treatment, amelioration or management, a prophylactically ortherapeutically effective melanogenesis-inhibiting amount of acombination of claim 72, wherein the like acting agent is apharmacologically active agent.
 77. The method of claim 76, wherein thelike-acting agent is a skin lightening compound.
 78. A method foraltering or restoring pigmentation in mammalian skin, hair, wool or furcomprising administering to the mammalian skin, hair, wool or fur anamount, which is effective to alter or restore pigmentation in mammalianskin, hair, wool or fur, of a combination of claim 72, wherein thelike-acting agent is a cosmetically active agent.
 79. The method ofclaim 78, wherein the like-acting agent is a skin lightening compound.80. A method for inhibiting melanogenesis comprising administering to amammal an effective amount of a plant extract containing compound of anyone of claims 1-51.
 81. The method of claim 80, wherein the plantextract is derived from the fruit of Maclura pomifera (Osage orange).82. The method of claim 80, wherein the plant extract is an ethanolextract of the fruit of Maclura pomifera.
 83. The method of claim 80,further comprising an additional active agent.
 84. The method of claim82, wherein the active agent is a pharmacological agent, a skinbrightening agent or a skin lightening agent.
 85. The method of claim80, wherein the effective amount of plant extract inhibits melanogenesisby about 10% or about 50%.
 86. The method of claim 80, wherein theeffective amount of plant extract prevents, treats, ameliorates ormanages a disease or condition involving undesired or aberrantmelanogenesis.
 87. The method of claim 80, wherein the effective amountof plant extract alters or restores pigmentation in mammalian skin,hair, wool or fur.
 88. The method of claim 80, wherein the effectiveamount of plant extract treats a disease for which a melanogenesisinhibitor is indicated.
 89. The method of claim 80, wherein theeffective amount of plant extract lightens or reduces pigmentationlevels in said mammal.
 90. The method of claim 80, wherein the effectiveamount of plant extract lightens or reduces pigmentation levels ofhyperpigmented sites on skin.
 91. A topical formulation comprising acomposition for cosmetic or dermatological use, said compositioncomprising a plant extract of claim 80 containing a prophylactically ortherapeutically effective amount of compound of formula I.
 92. Acombination of a plant extract of claim 80 and a like-acting agent. 93.The combination of claim 92, wherein said like acting agent is selectedfrom a cosmetic ingredient and a pharmacologically active agent.
 94. Thecombination of claim 93, wherein the cosmetic ingredient is a skinlightener or a skin brightener.
 95. The combination of claim 93, whereinsaid pharmacologically active agent is another melanogenesis inhibitor.96. A method for inhibiting melanogenesis by melanocytes comprisingadministering to the melanocytes an effective amount of a plant extractcontaining compound of formula I in combination with a like-actingagent.
 97. The method of claim 96, wherein the effective amount of plantextract inhibits melanogenesis by about 10%.
 98. The method of claim 96,wherein the effective amount of plant extract inhibits melanogenesis byabout 25% or about 50%.
 99. The method of claim 96, wherein theeffective amount of plant extract prevents, treats, ameliorates ormanages a disease or condition involving undesired or aberrantmelanogenesis.
 100. The method of claim 96, wherein the effective amountof plant extract alters or restores pigmentation in mammalian skin,hair, wool or fur.
 101. The method of claim 96, wherein the effectiveamount of plant extract treats a disease for which a melanogenesisinhibitor is indicated.
 102. The method of claim 96, wherein theeffective amount of plant extract lightens or reduces pigmentationlevels in said mammal.
 103. The method of claim 96, wherein theeffective amount of plant extract lightens or reduces pigmentationlevels of hyperpigmented sites on skin.